The best alternatives to Compressio are Realmac Software, BZG, and TinyJPG. If these 3 options don't work for you, we've listed a few more alternatives below.
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Notion— Get over $6,000 worth of Notion + unlimited AI, for free
PixelDrive uses AI to compress photos down to as little as 10% of their original size without compromising on quality or resolution. Users can link their existing Dropbox storage account (with Google Drive coming soon), and compress all photos stored on those platforms.