Recently, I tested a batch of JPGs that had already been compressed by websites:
📸 4,624 images
💾 Original: 1.41GB
📦 After ZIP: 1.41GB, almost no change
⚡ After ImgZilla compression: 0.75GB
🔥 Final savings: 46.8% ≈ 662MB
Why ZIP doesn't work?
Because JPG is already a compressed format, ZIP mainly just "packs" things, leaving almost no room to further compress the already encoded images.
Professional image compression tools do re-encode the image data, so even if an image has been compressed once by a website, there is still potential to save space.
Also, the compression in this test did not come at the cost of resolution:
- ✅ Image dimensions unchanged
- ✅ Filenames unchanged
- ✅ Folder structure unchanged
- ✅ Compression in place
If you have hundreds of GB of images on your Mac, NAS, or server, the real thing worth doing is not "zipping them again", but starting with the images themselves.
#ImageCompression #MacSoftware #ComputerTips #NAS #StorageSpace #ProductivityTools #IndieDeveloper