How to compress a JPG on Mac
Right-click the JPG in Finder and choose FileMate › Compress Image. FileMate saves photo compressed.jpg next to the original, re-encoded at 80% quality and the same dimensions, which for most camera photos makes a much smaller file with no visible difference. For more, choose Stronger or Maximum. Preview can also do it, one photo at a time, with the Quality slider in File › Export.
The JPG is compressed on your Mac, never uploaded.
Compress a JPG with FileMate
- Select one or more JPG files in Finder.
- Right-click and choose FileMate › Compress Image.
- The smaller copy is saved next to the original, as name compressed.jpg.
- For a smaller file, click Want a smaller file? and try Stronger (65% quality) or Maximum (55%, longest side 2048 px).
Compress a JPG with Preview
- Open the JPG in Preview.
- Choose File › Export.
- Leave the format on JPEG and move the Quality slider left. Preview shows the file size.
- Save it under a new name.
That gives precise control over one photo. For a batch of photos, it becomes repetitive: FileMate compresses every selected JPG in one step.
How JPEG compression works
JPEG is a lossy format. It splits the image into small blocks and throws away fine detail the eye is least sensitive to. The quality setting controls how much is discarded.
- 90–100%: close to the original, large files.
- 75–85%: the practical sweet spot for photos. Differences are hard to see at normal size.
- Below 60%: visible blockiness, especially in skies, gradients and around text.
Camera and phone photos are often saved at 90% or more, which is why re-saving them at 80% makes them much smaller.
When compressing a JPG doesn’t help much
- It’s already compressed. A JPG that was saved at 70% has little left to take out. FileMate says “Already well compressed” instead of saving a copy that’s barely smaller.
- It’s a screenshot or graphic. Text and flat colours compress badly as JPEG and show artefacts. PNG is usually better for those.
Does compressing a JPG lose quality?
Some, always: each JPEG save discards detail. At FileMate’s Safe level (80%), the loss isn’t visible in normal viewing for typical photos. Because FileMate always works from the original, compressing never stacks one lossy save on another unless you compress the compressed copy yourself.
Get FileMate
For photos you send, post and upload every week, FileMate puts JPEG compression in Finder’s right-click menu. The original stays untouched, and the file never leaves your Mac.
Normal price €9.99, now €4.99 incl. VAT
One payment, no subscription. macOS 14 Sonoma or later, Apple silicon or Intel.