Free Image Scaler
Upload forms and job portals often cap attachments at a specific size - 100KB, 200KB, 500KB, or 2MB. Guessing at a quality slider until you land under the limit is slow and unreliable. This page explains how to hit an exact size the first time.
Most compressors only give you a quality percentage, which tells you nothing about the file size you will end up with. Target Size mode works backwards from the number you need: it re-encodes the image at progressively lower quality and, if quality alone cannot get under the limit, reduces the resolution as well, until the result fits. That is why it can promise an exact ceiling where a quality slider cannot.
A 100KB ceiling is comfortable for a headshot or a document scan, and tight for a detailed landscape photo. If your image is large and busy, expect the tool to reduce resolution as well as quality to get there - the result will be noticeably softer than the original. If the form allows it, 200KB or 300KB usually keeps visible quality much closer to the source.
JPG is the right default for photographs at a small size limit. PNG is lossless, so it cannot be squeezed by quality alone and will usually need a resolution reduction to reach 100KB - use it only when you need transparency or sharp text. WebP typically reaches the same apparent quality in a smaller file than JPG, so try it first if the site accepts it.
Target Size mode guarantees the result is under the limit you set, landing close to it rather than exactly on it. A file slightly under 100KB is what upload forms require anyway.
It depends on the source. A portrait or document usually still looks fine. A large, detailed photo will lose visible detail, because reaching 100KB may require reducing resolution as well as quality.
No. Compression runs entirely in your browser, so the image never leaves your device.