Mac image compressors: Squish, ImageOptim or Clop?

Shrinking 1 photo for an email and keeping every new screenshot light are different jobs. Decide whether you need an occasional export, a lossless pass over images, or files that shrink as they arrive.

Quits publishes Squish. This review compares documented capabilities, checked 19 October 2026, with the developers’ own pages; it is not a hands-on benchmark, and it does not claim any size saving or speed for any app.

Which approach fits?

Choice	Consider it when	Check before choosing
Preview, Finder and QuickTime Player	You shrink a file now and then	Each tool makes a new file, one task at a time
Squish	You want images and videos smaller in the same format, or a watched folder	macOS 14 or later; access to the folders you choose
ImageOptim	You want a free, open-source optimizer that preserves quality by default	It removes metadata by default; its page describes images, not video
Clop	You want clipboard and screen-recording optimization, or format conversion	Some features are Pro or capped per session; macOS 14 or later

Start with what macOS already does

Apple’s Preview guide explains File > Export: choose HEIC, JPEG, JPEG-2000, OpenEXR, PDF, PNG or TIFF, and with JPEG or JPEG-2000 you can adjust the image’s quality. In the Finder, Quick Actions include Convert Image: Control-click the file, choose Quick Actions, click More, choose Convert Image, then pick a format and a size. For a movie, QuickTime Player’s File > Export As offers 720p and 480p, saved as a QuickTime movie using H.264.

If you shrink a picture once a week, those tools may be enough. An app earns its place when the work repeats or you want files to keep their format without choosing settings each time.

Squish reviewed: same format, as files arrive

Squish takes PNG, JPEG, HEIC and WebP images and MP4 and MOV videos, and returns them smaller in the same format: a JPEG stays a JPEG. You drop files on its window, its Dock icon or its menu bar icon, or let it watch your screenshots folder (or any folder) so each new file gets smaller a moment later.

Squish browser Demo listing a photo, a screenshot and a screen recording after compression — A still from the Squish browser Demo, a simulation that runs in the browser, not the native app. File sizes shown are examples, not measured results.

One slider goes from smallest to most detail, with an optional maximum width; PNG stays lossless at 100. GPS data comes out of photos and videos, while the date, the camera and the rest stay. You can drag a line across the picture to compare before and after, and put the original back from the Trash in a click. You can also send files from the Finder’s Services menu or squish them in a shortcut. It all happens on your Mac.

The limits: Squish requires macOS 14 or later and asks for access to the folders you choose, to save next to your files and watch the folders you pick. It keeps formats rather than converting them, so if you need HEIC turned into JPEG for a friend, Finder’s Convert Image does that and Squish does not.

When ImageOptim is the right starting point

ImageOptim is free and open source under GPL v2 or later, and requires macOS 11 or later. Its page says it preserves image quality exactly by default, with an optional lossy mode for JPEG, SVG, animated GIF and PNG, and that it removes EXIF data, embedded thumbnails, comments and unneeded color profiles unless you turn that off. The GitHub repository shows commits in July 2026. Start here if you want a no-cost, inspectable tool, need SVG or GIF, or want more metadata gone than location; its page covers images only.

When Clop deserves a closer look

Clop optimizes images, videos, PDFs and audio. It can optimize an image every time you copy it to the clipboard, a screen recording as soon as you stop it, and files in a watched folder, and can convert to formats such as WebP, AVIF and HEVC. Its page says processing stays on the device and that it automatically converts less compatible formats like HEIC and MOV, the opposite choice from Squish. The free version has no time limit, with some features capped per session; Pro is a one-time lifetime license with a 14-day trial. It requires macOS 14 or later.

Choose around the files you handle

For an occasional photo or clip, use Preview, Finder or QuickTime Player. For free lossless image optimization, try ImageOptim. For clipboard, PDF or conversion workflows, look at Clop. For screenshots and videos that shrink in place and stay in their format, with location removed, try the Squish Demo.

Squish uses a one-time purchase; its current price and the House Rules are shown below. ImageOptim and Clop belong to their respective developers; Quits is not affiliated with them.