11 Best Online Image Optimizer Tools Compared (Real Test Data)

Hunting down a great online image optimizer that will fit your needs can feel like a never-ending search. The truth is that there are a lot of options to choose from, and while many of them do have some overlap between them, they’re not all the same – which is why you need a way to compare them. Welcome to the way.

In this post, we’re going to review 11 web-based image optimizers, including key information about each one. We’ll also share some real test data based on a compression experiment we ran using a JPEG and a PNG. Plus we’ll add in what we love about each tool, and what we think it could do better.

Best web-based image optimizer tools tested and compared

Online image optimizer tools help you compress images without a perceivable loss in quality.

To give you an idea of how much compression is possible, we put 11 different popular tools to the test. We used two identical images – one in a JPEG format and the other in a PNG format – to conduct the experiment. The approximate file size of the JPEG was 791 KBs, while the approximate size of the PNG was 1.4 MB.

You can see the two images that we processed below. Note the bottom center, which shows you the original file size prior to being put through each optimizer.

Below are the results of our image optimization experiments:

💡 Note: The compressed sizes presented by each tool were not used to calculate their performance. Instead, the file information for each image was checked on the hard drive after it was downloaded. This was then compared against the original sizes, also taken from the hard drive. This was done for consistency and accuracy reasons.

Now, let’s dive into the tools in more detail… 🪂

1. Optimole Image Compressor

The Optimole image compressor is our own free online tool that you can use to compress JPEG, PNG, and WebP image files. It’s easy to use and offers extremely fast results. You can process up to five images at a time, with each image being no larger than 5 MB.

Once you receive the results, you’ll also be able to compare the original version of the image with the compressed version. The tool gives you a back and forth slider for this purpose:

In addition, you’ll notice that there’s an option to toggle between high, medium, and low compression. This is useful in case you find that the highest level dulls the original image down too much, in which case you can go for the medium or low options.

In the meantime, the compression results from the test are below:

Results 📉

• JPEG Image file saving: 94.77%This result was obtained by choosing the high level, but even at the medium level, the result still came in only about 1% less.
• PNG Image file saving: 74.78%This result remained the same, regardless of choosing low, medium, or high.

Key information 🗝️

• How many images at once: 5
• Max file size of each image: 5 MB
• Input accepted: JPEG, PNG, WebP
• Output choices: Image outputs are provided in the same file type as the input format

What we love ❤️

The JPEG compression capability of Optimole is unmatched. It surpassed all of the other optimizers on this list (though Compress Now did come close). The interface is also arguably the most user-friendly. Some of the other tools are very busy and it can take a moment to figure out what you need to do, but Optimole is very straightforward.

What could be better 💔

While the tool offers the highest level of JPEG compression among the rest – which is probably going to be the main decision-making factor for most people – it could do a better job with PNGs.

It could also offer higher limits for bulk uploads. Five images at a time might start to feel tedious after the first few rounds if you have 50 images to process.

Finally, the image size cap of 5 MB could be a little larger as well. While not an issue for most website purposes, since website images (other than maybe professional photographers) rarely go that high, it’s still nice to be able to have the option to compress a larger file.

💡 Note: If you have a website and it was built with WordPress, then it’s worth mentioning that we also have a free WordPress plugin version of Optimole that goes above and beyond simple compression. The best part is that once you set it up, it runs on auto-pilot. It saves a boatload of time because you don’t have to do these compressions manually. Check it out for yourself.

2. Compress Now

Compress Now is an excellent image optimizer tool that allows you to compress three of the most common image file types: JPEG, GIF, and PNG.

It has a few other useful features, including allowing you to choose the degree to which you’d like to compress your uploaded image. The maximum file size you can upload is 9 MB, which is well above and beyond our two example images.

When running the test, we set the compression amount to 65%. To the naked human eye, you could barely tell the difference between the original and the much lighter compressed version. The compressed image was a smidgeon less shiny, but you’d have a hard time telling which is which if they were shuffled and you had to pick out the compressed versus the original.

Results 📉

• JPEG Image file saving: 93.92%
• PNG Image file saving: 96.54%The output of this was a JPEG file, so it’s not a true 1 to 1 comparison, because the compression also included a conversion from PNG ➡️ JPEG. ⚠️

Key information 🗝️

• How many images at once: 10
• Max file size of each image: 9 MB
• Input accepted: JPEG, PNG, GIF
• Output choices: JPEG Only

What we love ❤️

The JPEG compression is really exceptional and second only to Optimole. However, unlike Optimole, you can upload double the amount of images at once. The file size limit is higher as well. This makes it an attractive choice if you plan on bulk processing a moderate amount of images and you don’t mind that they will all come back to you as JPEGs.

What could be better 💔

You can probably already guess what we’re going to say here. The lack of image file type output is really a drawback with Compress Now. If you upload a PNG, it shouldn’t be a tough ask to get back a PNG, but for whatever reason, this tool doesn’t think so. They are #TeamJPEG all the way.

3. Online Image Tool

The Online Image Tool is popular among Reddit users and for good reason – it gets the job done, it’s free, and it has some other extra features that sometimes come in handy when you’re working with images. These include file type conversion, image resizing, and image rotating.

On the compression front, it handles both JPEGs and PNGs really well, and does a fine job with WebP files also.

Results 📉

• JPEG Image file saving: 90.86%
• PNG Image file saving: 84.11%

Key information 🗝️

• How many images at once: Unlimited
• Max file size of each image: No Limit
• Input accepted: JPEG, PNG, GIF, WebPThey don't openly state that there's support for WebP, but we tested it with a separate image and it worked beautifully.
• Output choices: Image outputs are provided in the same file type as the input format, however, there is a separate conversion tool you can use to change your files to JPEG, PNG, or WebP.

What we love ❤️

The user interface on this tool is probably tied with Optimole for first place. It’s so intuitive and beginner-friendly. Aside from the before-and-after comparison slider, the other standout aspect of the interface is that you can add more images from the same post-processed screen. In other words, you don’t need to click back to start again. That can come in handy if you have images in different folders and you’re trying to get them all compressed before downloading them all at once.

Another huge standout feature is that Online Image Tool has no cap on either file size or on the number of images you can process simultaneously.

What could be better 💔

There really aren’t too many drawbacks, unless you want to work with some less commonly used file types like the newer AVIF format or SVGs for example. Other than that, if you’re using standard JPEGs, PNGs, GIFs, or the ever-more-popular WebPs, then the Online Image Tool is an exceptionally good image compressor.

4. JPEG Optimizer

JPEG Optimizer is a good solution to consider if you need to compress larger quantities of images simultaneously. It supports up to 20 in one go, which is double what Compress Now lets you do, and quadruple the amount Optimole allows.

The default compression is set to 80% but we reduced it to 65% to stay consistent with the previous Compress Now test. You can adjust it from anywhere between 1-99%. At the 65% level, we were able to compress the image into almost half of its original size in both JPEG and PNG, and the quality wasn’t visibly any different.

If you wish, you can also set the maximum size of the image (default is unlimited) and resize its dimensions. Once the tool compresses the image, you can download it and use it anywhere you need.

Results 📉

• JPEG Image file saving: 90.80%
• PNG Image file saving: 88.49%

Key information 🗝️

• How many images at once: 20
• Max file size of each image: No limitWe tested it with a separate PNG that was 45.8 MB and it compressed it down to 10.9 MB with no problem.
• Input accepted: JPEG, PNG, GIF
• Output choices: JPEG, PNG, GIF

What we love ❤️

Despite its name implying that it’s only focused on JPEGs, the JPEG Optimizer is one of the most flexible options on the list when it comes to file type outputs. In fact, it’s only one of three tools on the list (with Ezgif and Squoosh being the other two) that lets you choose a file type output that’s different from the input.

In addition, the bulk upload limit capacity being at 20 is also pretty good. It’s not the highest limit, but it’s among the higher options.

Finally (and ironically, given its name), it demonstrated the highest compression capability for PNG files in our test.

What could be better 💔

The tool is excellent if all you need to work with are JPEGs, PNGs, and GIFs. However, if you’d like to work with some more modern image formats like WebP or even AVIF, then you’ll need to check out some of the other options on this list instead.

5. Tiny PNG

TinyPNG – JPEG, PNG & WebP image compression

Author(s): TinyPNG

Current Version: 3.4.4

Last Updated: September 2, 2024

tiny-compress-images.3.4.4.zip

90%Ratings 200,000+Installs WP 3.4+Requires

TinyPNG offers respectable levels of compression and decent bulk upload limits. You can process up to 20 images at a time, with each image being no larger than 5 MB.

After compression, images can be downloaded to your computer or saved to Dropbox. Tiny PNG is also very convenient for WordPress aficionados because it has a free plugin you can use to automatically compress the images on your site.

Results 📉

• JPEG Image file saving: 88.58%
• PNG Image file saving: 81.63%

Key information 🗝️

• How many images at once: 20
• Max file size of each image: 5 MB
• Input accepted: WebP, JPEG, PNG, APNG
• Output choices: Image outputs are provided in the same file type as the input format

What we love ❤️

If you frequently rely on Dropbox to store your images, then the direct connection to it is a big timesaver. When the tool is done compressing, instead of downloading the processed file(s) to your hard drive, you can click on the Dropbox logo. This will then prompt you to log into Dropbox. From there you can save the files directly into one of your Dropbox folders. That’s convenient.

What could be better 💔

The max image file size is only 5 MB, which doesn’t make it a good option for working with larger or higher resolution images.

6. Optimizilla

Another easy to use image optimizer tool that compresses JPEG, GIF, and PNG formats. If you choose Optimizilla, you can upload up to 20 images. The tool adds each image to the queue and compresses it automatically through lossy optimization.

Just like Optimole, Optimizilla also has a slider feature that lets you view the original image and the processed one. In addition, you can see by what percentage every image was compressed and remove the images that you don’t want to save.

Another great aspect of using Optimizilla is that if you’re not happy with the default compression level, then you can modify its quality manually. There’s a secondary slider to the right of the preview one, and it lets you adjust the quality until you get a result that’s acceptable to you. Check it out below:

When you’re done, you can either download all the images in bulk or one at a time.

Results 📉

• JPEG Image file saving: 85.01%
• PNG Image file saving: 75.98%

Key information 🗝️

• How many images at once: 20
• Max file size of each image: No limitWe tested it with a separate PNG that was 45.8 MB and it compressed it down to 16.8 MB with no problem.
• Input accepted: JPEG, PNG, GIF
• Output choices: Image outputs are provided in the same file type as the input format

What we love ❤️

While Optimizilla doesn’t have a single thing that really makes it stand out from the pack, it does a great job of offering a mixture of many of the features that we like about the other tools. For example, it has the before-and-after slider and the higher bulk upload limit of 20. When you combine that with its uncapped file size and solid compression results for both PNGs and JPEGs, it makes Optimizilla a strong option.

What could be better 💔

Being stuck with the same output format as the input file is somewhat limiting. Granted, Optimizilla is not the only tool that suffers from this limitation, but there are others on this list where that’s not an issue. It would also be nice to see support for newer file types, especially WebP.

7. JPEG.io

To convert images from several different formats into a compressed JPEG, you can try JPEG.io. It’s capable of accepting a wider variety of image types compared to most online image optimizer tools.

Beyond that, you can also import image files directly from your Google Drive or Dropbox. JPEG.io will then process and return them to you in a zip file.

Results 📉

• JPEG Image file saving: N/AThe tool would not accept JPEG inputs as of the time of the most recent update to this article.
• PNG Image file saving: 92.92%The output of this was a JPEG file, so it’s not a true 1 to 1 comparison, because the compression also included a conversion from PNG ➡️ JPEG. ⚠️

Key information 🗝️

• How many images at once: UnlimitedWe tested up to 40 images at once and the tool processed them.
• Max file size of each image: No limitWe uploaded a large PNG file of 45.8 MB and it compressed it down to a 5.64 MB JPEG.
• Input accepted: PNG, GIF, SVG, BMP, EPS, PSD, TIFF, WebP
• Output choices: JPEG Only

What we love ❤️

The fact that there is no file size limit makes JPEG.io a perfect option for anyone with very high resolution images that wants to reduce their weight. Similarly, for bulk image processing, the no limit factor is very convenient. Instead of having to repeat the compression process over and over, you can just drag and drop all of your files at once and let the tool work its magic.

What could be better 💔

The fact that the output format is limited to a single file type is pretty terrible. If you want to receive anything other than JPEGs back, then you’ll need to opt for a different tool from this list.

Also, it’s worth mentioning that as of the time of this update JPEG.io seems to be having difficulties with JPEG inputs. This wasn’t an issue previously, but after trying several JPEGs of varying sizes, they all came back with an error. Hopefully, by the time you read this, they’ll have fixed the problem. The other input formats seemed to work fine.

8. ImageRecycle

The navigation on this website is not as intuitive as it could be, but despite its minor shortcomings, it’s still a great tool. If you only have one image (or PDF) you need to compress, you can drag and drop the file directly onto the page (or click to upload it). Otherwise, if you have multiple images, then you’ll need to click on the “Try full optimizer” button.

One really helpful and unique feature about ImageRecycle is that it gives you a free report about your website with details of images that need optimization. Simply type in your website’s URL to obtain this report.

To access premium features like image resizing, wiping metadata, and lossless compression, you’ll have to opt for their premium plans. You can take your pick from different price points at $10 (processes about 10,000 images), $20 (~30,000 images), and $50 (~100,000 images).

Results 📉

• JPEG Image file saving: 87.18%
• PNG Image file saving: 79.52%

Key information 🗝️

• How many images at once: Unlimited
• Max file size of each image: 10 MB
• Input accepted: JPEG, PNG, GIF, PDF
• Output choices: Image outputs are provided in the same file type as the input format

What we love ❤️

ImageRecycle is the only compressor on this list that offers support for PDF files. That’s a unique selling point and can be useful for certain users. For example if you have an ebook or a technical report that’s in PDF format and you want to reduce its size, then you now have a tool to do that.

The premium tools are also very nice, but of course you have to pay for those.

What could be better 💔

If you upgrade to the premium version, then you can choose between lossy and lossless compression. Otherwise the default setting in the free tool is lossy. In contrast, the next option on the list, Compressor.io, gives you this choice even in the free version.

Also, in some weird effort to seem “more beginner-friendly” they don’t refer to the two types of compression by their names and instead call them “best saving” and “original quality.” Sure, lossy and lossless is technically “jargon,” but it’s not exactly rocket science. They could just write the normal names.

Finally, the overall navigation needs improvement. It doesn’t make sense that the default homepage only lets you upload one image at a time, but then if you want to bulk upload you have to go to the “full optimizer.” Why not just start off with the full optimizer?

9. Compressor.io

If you’re looking at high levels of compression that can save you hundreds of KB, take a close look at Compressor.io. It can reduce file sizes by close to 90%. It compresses JPEG and PNG images without loss of pixels, and lossy compression for other file types. However, the file size cannot exceed 10 MB.

Compressor.io also offers a before-and-after slider similar to some other tools on this list. This lets you compare the original and optimized images side by side. In addition to the standard download, it also has the convenient option of saving the processed images directly to Google Drive or Dropbox.

Results 📉

• JPEG Image file saving: 91.71%
• PNG Image file saving: 77.61%

Key information 🗝️

• How many images at once: 10
• Max file size of each image: 10 MB
• Input accepted: JPEG, PNG, SVG, GIF, WebP
• Output choices: Image outputs are provided in the same file type as the input format

What we love ❤️

Compressor is one of only two tools on this list (with Ezgif being the other) that lets you decide if you want to do lossy compression or lossless compression without having to upgrade. Most of the other options don’t even tell you which compression type they use (though presumably it’s lossy), much less let you choose between them. When you add in that Compressor also supports multiple file types – including SVG and WebP – you’ve got a compelling set of reasons to use it.

What could be better 💔

There’s not too much to complain about with this tool other than perhaps increasing the bulk upload limit to at least 20. While 10 at a time isn’t the lowest on the list, it can feel inconvenient if you have a lot of images to process.

Besides that, the developers could do a better job with explaining the features in the Pro plan. For example, with regard to the bulk upload limit, if you try to process more than 10 images at a time, it tells you that you need to upgrade to increase the limit. But then nowhere does it tell you how much the limit will be increased by. Overall, they aren’t doing the best job at selling their Pro plan.

10. Ezgif

As is the case with several of the tools we’ve presented here, Ezgif is another one that has a somewhat misleading name. While it obviously supports GIF compression, it’s not solely limited to that. It also works with JPEGs, PNGs (including APNGs), and WebP files.

For JPEGs, the default compression is set to 90% quality, but we reduced it to 65% for consistency with the previous tests where quality / compression was adjustable.

Apart from that, Ezgif is arguably the most robust tool on the list in terms of other editing options that go beyond just compression and resizing. You can convert between all types of formats, add overlays and text, crop, and more.

Results 📉

• JPEG Image file saving: 90.85%
• PNG Image file saving: 23.56%

Key information 🗝️

• How many images at once: 1
• Max file size of each image: 200 MB
• Input accepted: JPEG, PNG, APNG, GIF, WebP
• Output choices: GIF, JPEG, PNG, AVIF, SVG, WebP, JXLAvailable for JPEG and WebP only., MNGAvailable for WebP only., spriteAvailable for WebP only.

What we love ❤️

There’s a lot to love about Ezgif, starting with its enormous file size cap of 200 MB. It’s unlikely that the average person will ever need to optimize an image that would come anywhere near close to that, which effectively gives Ezgif quasi-unlimited file size support.

It also lets you process images that have been uploaded elsewhere on the web. All you have to do is enter their public URL, and Ezgif will pull the image into its system for processing.

If that wasn’t unique enough, it has a range of editing tools that allow you to tweak your image in various ways prior to compressing it. Some of these tools are offered in a few of the other options on this list, but only in the paid versions, whereas with Ezgif, you get them for free.

Finally, after you compress your image, you can convert it to other file types, including AVIF, WebP, and SVG.

What could be better 💔

One of the big downsides with Ezgif is the fact that you can only upload a single image at a time. That makes it absolutely annoying to use if you need to bulk upload images. Bizarrely enough, for some of the other tools in its arsenal, it supports up to 2,000 files at a time. It seems like it likes to work in extremes when it comes to this one issue.

There’s also the elephant in the room: the PNG compression result was roughly only a third of many of the other tools on the list and even worse when compared against the PNG frontrunners (JPEG Optimizer and Tiny PNG). This makes it a particularly poor choice for PNG compression specifically.

11. Squoosh

Squoosh has a real modern, cutting edge vibe to it. Not only does it support the latest image file types like AVIF and QOI, but it also lets you choose from a range of outputs, including some of the latest formats that are still in beta (e.g., WebP 2.0). Of course the standard JPEG and PNG are fully supported as well.

Results 📉

• JPEG Image file saving: 92.38%This result was obtained by choosing the MozJPEG compression method at a quality level of 65%. When choosing the standard browser JPEG compression, also at a 65% quality level, the result was 90.80%. From a file type perspective, both the MozJPEG and browser JPEG choices will render as a standard JPEG, so for best results, always choose the MozJPEG.
• PNG Image file saving: 26.92%This result was obtained by choosing the OxiPNG compression method at the highest possible effort level of 6. When choosing the standard browser PNG compression, there was no compression result - it showed 0%. From a file type perspective, both the OxiPNG and browser PNG choices will render as a standard PNG, so for best results, always choose the OxiPNG.

Key information 🗝️

• How many images at once: 1
• Max file size of each image: No limitWe uploaded a large PNG file of 45.8 MB and it processed it with no issues.
• Input accepted: JPEG, PNG, WebP, AVIF, JXL, QOI
• Output choices: JPEG, PNG, WebP (including a new 2.0 beta version), AVIF, JXL, QOI

What we love ❤️

It’s extremely easy to shuffle between various output types and to tinker with other variables. You simply use the drop down menu on the output side to choose a format. If you want to see how your image looks in a different format (or with an adjusted variable), then you can do it instantly, right on the same screen. The new output will appear in front of you, with the before-and-after slider that some of the other tools have. The unique thing about this slider though, is that it lets you zoom in and out on the image so you can see the difference at a very fine level.

What could be better 💔

If you thought that Ezgif’s PNG compression was lackluster, then Squoosh will leave you equally disappointed. Even when choosing the “better” PNG compression method (OxiPNG), the result was still a subpar 26.92%.

With that said, if you’re okay with receiving back your image in a different format, then you’ll be quite pleased at the results. For example, we tested our example PNG with a JPEG output at the 65% quality threshold and received back a file that was roughly 95% smaller.

Aside from that, Squoosh’s interface can be a bit confusing to navigate if you don’t understand some of the terminology. For example, there are the compression types like MozJPEG and OxiPNG, but then there are also newer file types like QOI. A person who’s not familiar with those terms whatsoever, won’t understand the differences or what to make of them.

Last thoughts 💭

According to our results, Optimole is the best JPEG compressor with a 94.77% image compression result, while JPEG Optimizer takes the crown for best PNG compressor with 88.49%.

If max compression capability is your number one deciding factor, then your choice for JPEGs and PNGs is clear. However, if you have other needs that override needing the absolute highest compression, then you might consider one of the other options on the list.

Below is another handy table that can help you decide between some of those additional factors:

If you’d like to cross-reference the information above with the compression results one more time, then click here to go back to that table. Otherwise, happy compressing!

Do you have any questions about the best way to use these online image optimizer tools? Let us know in the comments and we’ll try to help!