FixMyPDFs
Free in-browser PDF tools that never upload your files
Free
Productivity
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Three tools on this page handle image compression, and they work in different places. Two run in a browser and one lives inside the Mac Finder.
ihateimg.cv offers 58 free image tools that run on the device, with no account, no watermark and no file-count limit. FixMyPDFs is free as well, but it centers on PDFs, with 69 browser tools that include compressing. FinderBuddy is a paid Mac app. It adds image compression and conversion to the right-click menu for a one-time price, starting at $9 at launch.
3 tools
Free in-browser PDF tools that never upload your files
Right-click file tools for Mac, built into Finder
Image tools that never upload your files