How to reduce an image’s file size on Mac
There are three ways to make an image file smaller: compress it, reduce its pixel dimensions, or save it in a more efficient format. On a Mac, the quickest is to right-click the image in Finder and choose FileMate › Compress Image. FileMate saves a smaller copy next to the original. If it needs to be smaller still, stronger levels lower the quality and then the dimensions.
FileMate compresses images on your Mac. Nothing is uploaded.
Make an image smaller with FileMate
- Right-click the image in Finder: JPEG, PNG, HEIC or TIFF.
- Choose FileMate › Compress Image.
- Check the saving in the result, for example “6.2 MB → 2.9 MB · 53% smaller”.
- Need more? Click Want a smaller file? and try Stronger or Maximum.
The copy keeps the original format: a JPEG stays a JPEG, a PNG stays a PNG. The original is never changed.
Compress, resize or convert?
| Method | What it changes | Good for |
|---|---|---|
| Compress | How much data stores each pixel | Photos that look fine but weigh too much |
| Resize | How many pixels the image has | Images far larger than where they’ll be shown |
| Convert | The format | PNG photos (to JPEG), or HEIC for sites that need JPG |
Resizing and compressing are different operations. A 4000 × 3000 photo compressed well might be 2 MB; the same photo resized to 2000 × 1500 has a quarter of the pixels and ends up far smaller at the same quality. Usually the best result comes from both.
What FileMate’s levels do
| Level | JPEG and HEIC | PNG and TIFF |
|---|---|---|
| Safe | 80% quality, same dimensions | Re-saved losslessly, same dimensions |
| Stronger | 65% quality, same dimensions | Longest side limited to 2560 px |
| Maximum | 55% quality, longest side 2048 px | Longest side limited to 1600 px |
FileMate starts at Safe by default. A copy is kept only if it’s at least 2% smaller; otherwise the result says the image is already well compressed.
With Preview
- Open the image in Preview.
- For smaller dimensions, choose Tools › Adjust Size, enter a smaller width, and click OK.
- Choose File › Export, choose JPEG, and drag the Quality slider to the left. Preview shows the resulting file size as you drag.
- Save under a new name.
Preview gives fine control over one image. It takes several steps for each file, and it’s easy to overwrite the original with File › Save by mistake.
Why a phone photo is so large
A 12-megapixel photo has 12 million pixels, and a 48-megapixel one four times as many. That’s far more than any screen shows: a large desktop display is about 5 to 15 megapixels, and an image on a website is often under 2. When a photo is only going to be seen on a screen, reducing its dimensions is the biggest saving.
Get FileMate
Right-click, Compress Image, done. FileMate makes the smaller copy on your Mac and leaves the original exactly as it was.
Normal price €9.99, now €4.99 incl. VAT
One payment, no subscription. macOS 14 Sonoma or later, Apple silicon or Intel.