Orpheus

Compress an Image to a Target File Size

Under 200 KB, under 1 MB — whatever the form demands.

Every tool runs entirely in your browser. Your files are never uploaded to a server.

There is no formula from quality setting to file size — it depends on the image. Hitting a target means encoding repeatedly and measuring, keeping the highest quality that fits under the limit.

How to use Compress Image to a Size

  1. Add your image. Drag it in or click to browse.
  2. Pick the limit. Match whatever the form demands — 100 KB and 200 KB are the common ones.
  3. Download. The result is the best quality that fits, not an arbitrary setting.

About compressing an image to a target file size

Compressing to a specific file size is a different problem from compressing generally, and it is one that most tools sidestep by offering a quality slider and leaving you to guess. The reason they do is that no formula exists: the bytes an encoder produces depend on what is in the picture. Fine detail, noise and texture are expensive to store; flat colour and gradients are cheap. The same quality setting applied to a portrait and to a screenshot can differ by more than an order of magnitude, which is why "set quality to 60" is advice that works for one image and not the next. The only honest approach is to encode, measure, and adjust — a binary search over the quality range, keeping the best result that fits. Ten iterations resolve a hundred-point range to within one point, and because each iteration is a full encode, that bound is what stops a large photograph taking noticeably long. What matters more than the search is what you feed it. Dimensions dominate file size, so reaching a small target from a twelve-megapixel original by quality alone forces the encoder into territory where blocking artefacts become obvious. Capping the longest edge first — 1600 pixels is ample for a form that will display the image at a few hundred — reaches the same target at a quality that still looks clean. This is why the resize option defaults to on rather than off, and it is the single most useful thing to understand about hitting an upload limit.

Frequently asked questions

Why can other tools not just set the right quality?
Because the relationship between a quality setting and the resulting file size depends entirely on the image. A flat graphic at quality 80 might be 40 KB and a detailed photograph at the same setting 900 KB. The only reliable way to hit a target is to encode, measure, and adjust.
Should I resize as well?
Almost always, and it does more than compression can. Reaching 100 KB from a 12-megapixel photo by quality alone produces visible blocking; capping the longest edge at 1600 pixels first gets there at a quality that still looks clean. Most forms display the image far smaller than the original anyway.
Why is WebP offered?
Because it reaches the same file size at a noticeably higher quality — typically 25 to 35 percent smaller than JPG for equivalent appearance. Use it if the form accepts it, and JPG if it does not, which is still the more common case for official uploads.
What if it cannot reach the target?
You get the smallest version it could produce along with its actual size, rather than an error. That usually means the target is very small relative to the image dimensions, and the fix is to cap the longest edge lower before compressing.
Why is PNG not an option?
Because PNG is lossless and has no quality dial — its size is determined by the content, so there is nothing to search. A photograph needed under a size limit has to become a JPG or a WebP. A PNG target can only be met by reducing dimensions or colours.

Last updated