Kompressor vs Preview
Preview is free and on each Mac, and it converts images. This is what Preview does well, where it stops, and when Kompressor is worth $14.99.
The short answer
For one image now and then, use Preview. It is free and already on your Mac. Kompressor is the better tool when you convert many images, when you need WebP, or when the file size is important.
Comparison
| Kompressor | Preview | |
|---|---|---|
| Price | $14.99 one-time, 3 free conversions | Free, part of macOS |
| WebP output | Yes | No |
| Batch conversion | Files and folders with drag and drop | Export Selected Images, one folder |
| Folder structure | Kept, with the Preserve folder structure setting | Not kept |
| Result preview | Original and result side by side, with file size | No preview of the result |
| Resize | In the same step | A separate step that changes the original |
| Remove metadata | All metadata, for all images | Location only, one image at a time |
What Preview does well
Preview opens almost every image format that Kompressor reads, because both use the image system of macOS. File > Export converts one image in a few clicks, and the export dialog shows an estimate of the file size for JPEG. Preview also crops, rotates and annotates images, which Kompressor does not do.
Where Preview stops
- WebP. macOS reads WebP but does not write it, so Preview has no WebP option. See how to convert PNG to WebP.
- Many images. Preview can export a selection of images, but with one setting for all of them, without a preview, and into one folder.
- Quality control. You do not see the compressed image before you export it. You must export, open the result and try again.
- Speed. In our test, Kompressor converted 32 iPhone photos from HEIC to JPEG in 0.3 seconds.
sips, the command-line tool that uses the same macOS encoder as Preview, needed 1.1 seconds.
Facts about other apps are from their official websites, as of November 2026.
Kompressor in short
Kompressor is an image converter and compressor for Mac (macOS 14 or later, or macOS 13 or later from the Mac App Store). It reads more than 50 formats, among them HEIC, WebP, AVIF and camera RAW, and writes more than 20, among them JPEG, PNG, WebP, AVIF and HEIC. It converts files and whole folders with drag and drop, shows the result and its file size before you convert, and works offline with no analytics. You get 3 free conversions with as many images as you want. A license is a one-time payment of $14.99.