Compress an image to under 1MB

Where a 1MB limit comes from

• Generous CMS and platform caps — the common default on content systems, job boards and marketplaces, chosen to stop genuinely huge files rather than to make anyone compress carefully.
• Cloud storage tidying — nobody enforces 1MB here, but it is the point where a photo library stops growing faster than the space you pay for.
• WhatsApp document-mode sends — sending a photo as a document preserves it exactly instead of re-compressing it, which is why people use that mode. Compressing to 1MB first keeps the transfer quick without handing the decision back to the app.

What 1MB actually looks like

Measured on the same 4K phone photograph used throughout this site (3840 × 2160, 1.52 MB), 1MB came out at 998.2 KB at the full 3840 × 2160, quality 85. Quality 85 is above the point where JPEG artefacts are detectable in normal viewing, and the pixel dimensions are untouched.

In other words: a third of the file gone, and there is nothing to see. That is what makes 1MB a safe default for bulk work — you are removing data the format was carrying inefficiently, not detail you would miss.

Compressing a whole photo library

This is the main reason people come to a 1MB target, and it deserves a warning before the advice.

Keep your originals. Compression is not reversible. If a photograph matters — family, work you were paid for, anything you might crop hard or print large later — compress a copy and archive the original somewhere you are not going to reclaim space from. The disk you save today is cheap; the detail is not recoverable.

With that said, for the large majority of photographs that are never going to be printed or heavily edited, 1MB is a sensible ceiling:

• A 4,000-photo library averaging 4MB each is 16GB. At 1MB each it is 4GB, with nothing visibly different.
• Screenshots, receipts, documents and anything already flat compress far below 1MB anyway.
• Photos you plan to edit should stay at full quality until you have finished editing them — every re-compression compounds on the last.

For a batch rather than one file at a time, our bulk compressor runs the same process across a whole folder.

If 1MB is more space than you need

For anything going onto a web page, considerably more. 500KB still keeps full dimensions on most photographs, and 200KB is where a page starts loading quickly on mobile data.