Why our image compressor is better
- Compress to an exact KB — most tools only offer a quality slider; ours hits 20KB, 50KB, 100KB or any size you type.
- 100% private — images are compressed in your browser and never uploaded to a server, ideal for ID photos and documents.
- Smart resizing — if your target is very small, it automatically reduces dimensions so it can still reach the size.
- Batch support and instant download, with no watermark, no sign-up and no limits.
Why upload forms demand an exact size
Government portals, university applications, job boards and exam registrations almost all cap file size — usually 20 KB, 50 KB, 100 KB or 200 KB. The limit exists because the system behind the form stores millions of these and was often specified a long time ago.
What makes it frustrating is that the form rejects the file after you have filled everything else in, and offers no help beyond the number. A quality slider does not solve that: you cannot know which quality setting lands under 20 KB without trying repeatedly. Targeting the number directly is the difference between one attempt and eleven.
How hitting an exact size actually works
The tool compresses, measures the result, adjusts and repeats — a binary search over the quality range until the output sits just under your target. That is why it takes a moment longer than a single-pass compressor and why the result is reliably under the limit rather than approximately near it.
Where it cannot reach the target by quality alone, it reduces dimensions as well. A 4000-pixel photo simply cannot become 20 KB while staying 4000 pixels wide, and no tool can change that.
Getting a usable photo at 20 KB
Small targets are achievable but the input matters enormously:
- Crop first. A passport photo cropped to the face compresses far better than the same face inside a full-body shot — there is simply less to describe.
- Plain backgrounds compress better. Detailed backgrounds cost bytes that add nothing to an ID photo.
- Use JPG, not PNG, for anything photographic. PNG is lossless and will not reach small targets at usable dimensions.
- Start from the original rather than a screenshot of it. Screenshots of photos are already degraded, and compressing degraded input twice looks it.
Why nothing is uploaded
Compression happens in your browser through the canvas API. Your image is read, redrawn and re-encoded on your own device, and the result is handed straight back.
That matters more here than on most tools, because the files people compress to an exact size are overwhelmingly identity documents — passport photos, signatures, certificates, ID cards. Those should not be sitting in a queue on someone else’s server. You can confirm no request is made by opening your browser’s network tab while you compress.
If the result looks bad
Three things to check before assuming the tool failed. Is the target realistic for the dimensions? 20 KB at 2000 pixels wide will look poor no matter what. Is the source already compressed? Recompressing a heavily compressed JPG stacks artefacts. Does the form accept a slightly larger file? Many state 100 KB but accept 200 KB — worth checking before you sacrifice quality.
For a straight format change without a size target, use the image converter. For iPhone photos, HEIC to JPG converts first so there is something to compress.