Best Image Compressors in 2026: the buyer's shortlist

For private, bulk work, ToAny is the best image compressor on this list. It compresses JPG, PNG, WebP and SVG files in your browser, and there are dedicated pages for JPG and WebP. A few other formats come back as another one: HEIC and JP2 as JPG, and BMP and similar as PNG. You drop one image or hundreds, choose Keep quality, Balanced or Smallest, or type a size to fit under per file, and download the results one by one or as a ZIP. The page states that nothing is uploaded and shows a counter of bytes sent.

There is no daily limit and no account. ToAny refuses a single picture larger than 120,000,000 pixels. It never returns a file larger than the one you gave it. If an image cannot shrink, you get the original back with a reason.

Compression always runs on your device. ToAny does have a server engine, but it is used only for 16 conversion pairs, such as old Word formats, and only after you consent for each upload. The only thing reported about a browser conversion is an anonymous count of the format pair.

The weak spots are real. ToAny has no GIF compression, no API, no command line, no folder or watch-folder support and no cloud import. Large batches are limited by your device's memory, which can bite harder on a phone. A JPEG above 40 megapixels only gets a lossless re-pack, which saves about 7 percent in our tests.

ToAny also converts 190 formats in 1,195 pairs and offers PDF tools, so it can stay your one tab for file jobs.

Squoosh is the other in-browser option, built by Google Chrome Labs. Its own description is an image optimizer that lets you compress and compare images with different codecs in your browser. You drop one image, pick a codec and settings, and watch the result next to the original.

The privacy position is close to ToAny's. The project README says Squoosh does not send your image to a server and that all compression happens locally. It also says Google Analytics collects basic visitor data, the before and after image size value, and PWA install type and time. No file content is mentioned.

Squoosh is open source under Apache License 2.0. The GitHub repository was created on 2018-03-07 and showed 26,033 stars when we read it on 2026-10-17. The last push was two days earlier, so it is maintained. The page can also be installed as a progressive web app.

In the sources we read, Squoosh states no file-size limit, price, batch feature or list of supported formats. Its design is about examining the trade-off between quality and size on an image. That is a strength for a designer or a developer picking a codec. We found no batch feature described, so check before you bring a whole folder of photos.

Its pages state no price, so we do not claim one.

If you only ever compress one picture at a time and like to see the difference before you save it, Squoosh is hard to beat.

Caesium is a free image compressor from SaeraSoft, with Matteo Paonessa named as the copyright holder. The vendor describes it as one of the most popular image optimisation programs available and claims it can compress pictures up to 90 percent without visible quality loss. That is a vendor claim, not a measurement.

The desktop app, version 2.8.5, comes as a Windows installer, a portable zip and a macOS disk image. According to its GitHub page it runs on Windows 10 (build 1809 and later), macOS 12 and later, and Linux, tested on Ubuntu 22.04 and Manjaro. It supports JPG, PNG, WebP and TIFF. The source is under GPL-3.0 and the repository shows 6,403 stars.

Caesium also has an online version that says images never leave your device. Its limits are tight: 20 MB per file and 10 files at a time. It supports three formats, JPG, PNG and WebP. We found no daily limit.

For automation, Caesium offers a command-line tool, which the vendor calls the heart of the program. We found no hosted API. The landing page loads Google AdSense, so expect ads on the vendor's pages.

Caesium wins over ToAny on offline use, TIFF support in the desktop app and the command line. It loses on the online limits, which are lower than ToAny's, where the stated cap is 120,000,000 pixels per picture and no daily limit.

We found no paid plan, although the site links to a donation page.

ImageOptim is a Mac app created by Kornel Lesiński. The vendor says it is free and open source, and it combines MozJPEG, pngquant, Pngcrush, 7zip, SVGO and Google Zopfli behind one drop target. Version 1.9.3 requires macOS 11 or later, and the vendor states plainly that the app only works on Macs.

It applies lossy compression to JPEG, SVG, animated GIF and PNG files. By default it removes EXIF metadata, such as GPS position and a camera's serial number, with an option to keep it. That matters if you publish photos. We found no format count or typical saving stated, so we cannot quote one.

The Mac app runs on your machine. The separate online uploader is different: the page says it uses the ImageOptim API, so files go to the web service. The API terms say images are temporarily cached on ImageOptim's servers and on those of its content delivery networks, with no deletion period stated.

The API is the paid product. The cheapest plan is $12 per month for 2,000 optimizations per month, then $49 per month for 16,000 and $245 per month for 100,000, with dedicated plans from $850. Cached requests are free and count once. The API also offers a free trial, with no limits stated.

The Mac app is available in 19 languages. ImageOptim Ltd is registered in England and Wales, with its registered office in London.

ImageOptim beats ToAny on GIF support, default metadata removal and an API for developers. It loses for anyone not on a Mac.

ShortPixel is a hosted service made in Bucharest, Romania. ShortPixel is a trademark of ID Scout SRL. It compresses JPG (including JPEG 2000 and XR), PNG, GIF, including animated ones, and PDF. HEIC files are converted to JPG, and it can convert images to WebP and AVIF. No total format count is stated.

The free online tool takes files up to 10 MB without logging in, and a login removes the restriction. The free plan includes 100 credits per month. Yearly billing is labelled 2 months free, but the plan amounts are not shown in the static page, so we do not quote a price.

Processing is on ShortPixel's cloud, so your images are uploaded. No single retention period is stated for standard optimisation. The privacy policy says data is kept only as long as needed for its purpose. If you cannot upload client or personal photos, that settles it.

The strength is the WordPress integration. ShortPixel offers plugins, Image Optimizer and Adaptive Images, with WP-CLI, multisite, WooCommerce, NextGEN Gallery and Cloudflare support. The vendor claims 1 million plus websites and 600,000 users worldwide.

The WordPress.org listing for the main plugin shows 4.5 out of 5 from 828 ratings, with 712 five-star and 75 one-star, and 20,337,543 downloads. Those are public counts, though they measure the plugin rather than the online tool.

Next to ToAny, ShortPixel wins on GIF, on conversion to WebP and AVIF, and on plugin automation. It loses on privacy and on the 10 MB free cap.

Compresto is a paid Mac app for compressing images, video and PDF files offline. The vendor says all processing happens on your Mac and files never leave your device. The copyright holder is named as Dinh Quang Hieu, and we found no founding year.

It handles PNG, JPEG, HEIC, WebP, TIFF and GIF images, MP4 and MOV video, and standard PDFs. The vendor claims typical reductions of 50 percent to 90 percent depending on source format, codec and quality preset. That is a vendor claim, and we have not tested it.

Batch handling is its headline feature. You can drop hundreds of files or entire folders, and they are processed in parallel with progress tracking. Folder monitoring is also offered. ToAny has nothing equivalent, so for a photographer clearing a large backlog on a Mac, Compresto is the stronger tool.

Pricing is a $49 one-time payment for 1 macOS device with lifetime updates, or $69 for 2 devices, shown against a struck-through $98. A yearly subscription also exists, but its price is not in the static page. There is a 3-day money-back guarantee and a 40 percent educational discount.

The app is macOS only, for Intel and Apple Silicon on macOS 13 and later. The homepage links a Windows waitlist while the FAQ says there are no current plans for Windows or Linux.

Compresto's free web demo accepts PNG, JPEG and WebP up to 5 MB. It runs on the vendor's server, which the page says stores nothing. The vendor's own page markup shows 4.8 from 100 ratings, which is self-published, not a review platform.