The Best Free Image Compressors in 2026

Every image compressor promises smaller files with no visible loss. Most of them deliver it, because the underlying encoders (MozJPEG, pngquant, libwebp) are open source and shared between them. What separates them is everything around the encoder: whether you can choose the quality, whether your images leave your computer, how many you can do at once, and what happens to the camera and location data inside each file.

How we compared them

We checked each tool against its own documentation, pricing and, for open source tools, its code repository, in October 2026. Where a vendor does not document a behaviour we say so. We include our own compressor and are specific about where it is not the right choice.

The short answer

1. Squoosh: best for getting one image exactly right

Squoosh is Google Chrome Labs’ open source compressor, and it remains the best tool for a single important image. You drop the image in and drag a divider across a side-by-side view of the original and the compressed version, changing the codec and quality until the artefacts appear, then back off. It includes MozJPEG, OxiPNG, WebP, AVIF and JPEG XL encoders, palette reduction for PNG, and resizing.

Squoosh states that it does not send your image to a server; the encoders run in your browser as WebAssembly. The site does use Google Analytics. Two caveats: it handles one image at a time, and development has been quiet since 2024. Its command-line version is marked as no longer maintained. The web app still works well.

2. TinyPNG: best for a quick batch on the web

Despite the name, TinyPNG compresses JPG, WebP and AVIF as well as PNG. You drop in up to 20 images of up to 5 MB each and download a zip. There are no settings: TinyPNG chooses the compression itself, and its PNG results are very good because it reduces the palette intelligently. It can also convert between formats, up to three times per session free.

Images are uploaded and kept for up to 48 hours. Metadata is removed by default, which can also drop the colour profile. For developers, the API allows 500 free compressions a month, and there is an official WordPress plugin.

3. ImageOptim: best for batches on a Mac

ImageOptim is a free, open source Mac app that runs a whole toolkit (MozJPEG, pngquant, Zopfli, SVGO and others) over every file you drag onto its window. It is lossless by default, so it will never make an image look worse; turning on lossy minification in the preferences gets much bigger savings. It strips JPEG metadata by default, and you can switch that off.

It does not mention WebP or AVIF, and the last released version, 1.9.3, is from October 2023, though the code is still being updated. For compressing existing JPG, PNG, GIF and SVG files it remains excellent.

4. Caesium: best for batches on Windows

Caesium is the free, open source desktop equivalent for Windows 10 and later and macOS 12 and later. It compresses JPG, PNG and WebP locally, with a quality setting, and can process whole folders. The latest release is from May 2025 and a version 3 is in development. There is also a browser version at caesium.app that says images never leave your device, takes up to 10 files of 20 MB, and has a keep-metadata option.

5. ShortPixel: best for WordPress

If your images live on a WordPress site, compressing them by hand is the wrong workflow. ShortPixel’s plugin, used on more than 300,000 sites, compresses each image when it is uploaded, can generate WebP and AVIF copies, and offers lossy, glossy and lossless modes. The free plan gives 100 credits a month, and each thumbnail WordPress generates costs a credit, so a single upload can use several. Images that would shrink by less than 5 percent do not use a credit.

Compression runs on ShortPixel’s servers rather than your host. It always keeps the colour profile even when EXIF is removed, which avoids a common colour shift.

6. iLoveIMG: the largest free web batches

iLoveIMG takes up to 30 files and 200 MB per task on the free plan, more than any other web tool here. Compression is automatic, with no quality control, and the compressor lists JPG, PNG, SVG and GIF. Images are processed on its servers and deleted afterwards, though it does not say how soon. It can pull files from Google Drive and Dropbox.

7. Compressor.io: lossy, lossless and custom modes

Compressor.io handles JPEG, PNG, SVG, GIF and WebP, and offers a keep-EXIF option. The free plan allows 50 compressions a day of up to 10 MB each, and images are deleted after compression. Choosing the exact quality is part of the Pro plan at US$50 a year, which is the main reason it sits below TinyPNG for most people.

8. Kraken.io: expert controls, tiny free files

Kraken’s free web interface has the most detailed controls of any web tool: separate JPEG and PNG quality from 1 to 100, chroma subsampling, and a choice of exactly which metadata to keep. The limit is the problem. Without a paid plan, each file can be at most 1 MB, which excludes most phone photos before you start. Paid plans start at US$5 a month.

9. ConvertStuff: JPG, WebP and PNG in the browser

Our JPG compressor, WebP compressor and PNG compressor run entirely in your browser. Images are processed on your own machine and never uploaded. EXIF data, including GPS location, is dropped, which is what you want before posting a photo publicly.

The JPG and WebP tools use your browser’s built-in encoder rather than MozJPEG, so Squoosh will usually squeeze a little more from a JPG at the same visual quality. The PNG tool does palette reduction, the technique behind pngquant: it cuts the image to at most 256 colours, dithers to hide the steps, keeps transparency, and adds colours back if a gradient would band. Its quantiser is simpler than pngquant’s, so TinyPNG or Squoosh may still get a PNG a little smaller. If nothing it makes beats your original, you get the original back rather than a bigger file.

Our compressor is quicker for routine work, and handles the conversions that save the most. Turning a photo saved as PNG into JPG or WebP typically does more than any compressor can.

10. Optimizilla: per-image control in the browser

Optimizilla, at imagecompressor.com, now compresses in your browser using WebAssembly and says files never leave your device. Older reviews that say it uploads images are out of date. It handles JPEG, PNG, WebP, GIF and SVG, gives each image its own quality slider with a before-and-after preview, and lets you set the colour count for PNG and GIF. It is free with no registration or daily limit. It does not support AVIF.

11. XnConvert: batch processing with everything else

XnConvert is a free batch processor for Windows, Mac and Linux that reads over 500 formats and can resize, strip metadata, watermark and convert in the same pass, with saved presets and watched folders. It runs locally. It is free for private, educational and non-profit use; business use needs a licence from €15. Its compression options are thinly documented, so test the settings on a few files first.

12. FileOptimizer: squeeze everything, losslessly

FileOptimizer is a free, open-source Windows tool that runs more than 90 optimisers over whatever you drop on it, including images, PDFs and Office files. It is lossless by default, with lossy compression as an option, and strips metadata. There is no quality slider, resizing or format conversion, and it overwrites files in place, sending the originals to the Recycle Bin. Work on copies.

13. EWWW Image Optimizer: WordPress, on your own server

EWWW, with more than a million active installs, compresses images on your own web server using the standard open-source optimisers, with no file-size cap and no monthly limit on the free version. It converts to WebP, resizes on upload, and removes EXIF data by default. The catch is that local mode needs a server function many shared hosts disable; there is a cloud fallback. AVIF and premium compression start at $8 a month.

14. Smush: WordPress, with a free bulk optimiser

Smush, also above a million installs, offers lossless and lossy compression, lazy loading and bulk optimisation with no image limit on the free version. Images are sent to its maker’s API for processing, and Smush does not publish how long they are kept. Free compression skips images over 5 MB, and WebP and AVIF conversion are Pro features. It backs up your originals by default.

Which one to use

• One image that has to look perfect: Squoosh.
• A handful of website images, no install: TinyPNG, or a browser tool if they are private.
• A folder of hundreds: ImageOptim on Mac, Caesium on Windows.
• A WordPress site: a plugin that compresses on upload, such as ShortPixel or TinyPNG’s own.
• Photos you are about to share: any local tool that strips EXIF.

Format matters more than the compressor

The largest savings rarely come from choosing a better compressor. They come from using the right format. A photograph saved as PNG can be several times the size of the same photo as a good JPG, and no PNG compressor will close that gap. A JPG converted to WebP is usually a quarter to a third smaller at similar quality, and AVIF goes further at the cost of slower encoding.

So decide the format first, then compress. Photos go to JPG, WebP or AVIF. Logos, icons and screenshots with sharp edges or transparency stay PNG or become SVG. Our comparison of AVIF, WebP and JPG covers which to pick for a website.