Melt guide

Make a photo less than 5 MB on Mac

Specific size targets — under 5 MB, under 2 MB, under 1 MB. Here's how to hit them reliably on macOS.

4 min read

Government forms want under 5 MB. Job applications want under 2 MB. Some insurance portals want under 1 MB. You hit Upload, the site rejects the file, and now you need to hit a specific number. Here’s how.

Why this is annoying

No image tool lets you say “make this 4.9 MB.” You set a quality and a resolution; you get whatever file size comes out. Hitting a target is a quick game of binary search — try quality 80, check the size, adjust.

The good news is there’s a predictable pattern: dropping quality and resolution both have known effects on file size. You can usually land within 10% of a target in one or two tries.

The native way

Preview’s export window shows a live size estimate. Open the photo, File → Export, pick JPEG, then drag the Quality slider while watching the “File Size:” number at the bottom. Save when you’re under your target.

If pixel dimensions are also too big, do Tools → Adjust Size first.

sips from Terminal is faster once you know roughly what to set:

sips -s format jpeg -s formatOptions 75 -Z 2400 photo.jpg —out smaller.jpg

Rough guide for a typical iPhone JPEG (12-15 MB original):

Run, check the size, adjust if needed. Two iterations almost always lands you under target.

The faster way

Download Melt does the iteration for you visually — drag the file in, set quality and resize, click compress, see the result. If it’s still too big, slide quality down and try again. Each pass is instant.

  1. Download Melt and open it.
  2. Drag the photo in.
  3. Set output to JPEG at quality 80, with Resize enabled (try 2000px to start).
  4. Click Compress and check the result. Adjust quality/size if needed.

For batch jobs where every file needs to be under the same threshold, set once and the same settings apply to the whole queue.

How much smaller will it really get?

The two levers are pixels and quality, and they compound. Halving the longest edge gives you roughly a 4x byte reduction; dropping quality from 95 to 80 gives you another 2x. Together, almost any photo can land under almost any target.

Honest tradeoffs

Under 1 MB on a portrait photo at full resolution is hard without visible quality loss. Resize first — most forms accept 1500-2000px wide easily, and the quality at that size at 75% is genuinely fine. The real reason your file is too big is almost never the compression setting; it’s the resolution.

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