Compress an image to a specific file size
Upload forms almost never ask for "a smaller photo". They ask for a number: under 50KB, max 100KB, no larger than 1MB. This page covers every common target, what each one realistically looks like, and which one to pick when the form gives you a choice.
Open the image compressor →Common upload limits and what each one means in practice
| Target size | Typical use | What to expect |
|---|---|---|
| 10KB | Old government portals, ID thumbnails | Very tight. Expect visible softness on a face. Use only when the form refuses anything larger. |
| 20KB | Exam forms, signature uploads | Workable for a signature or a plain-background headshot. Detailed scenes will smear. |
| 30KB | Application form photos | The floor at which a portrait still looks like a photograph rather than a JPEG artifact. |
| 50KB | The most common exam/application limit | The sweet spot for form photos — a face stays clean and the file still clears the cap comfortably. |
| 100KB | Job portals, registration forms, older CMSes | Roomy. A full-colour photo compressed here rarely shows visible loss. |
| 150KB | Council and university portals | Effectively lossless for a single portrait; useful when the form allows the headroom. |
| 300KB | Web page images, email attachments | Enough for a detailed landscape or product shot at normal screen sizes. |
| 500KB | Blog featured images | Generous for anything under about 2000px wide. |
| 800KB | High-detail web images | Only worth targeting if the image is large and detailed; most photos hit this without trying. |
| 1MB | Forums, general uploads, CMS defaults | The most forgiving common cap. Quality is essentially untouched. |
| 2MB and up | Print submissions, portfolio uploads | At this point you are usually resizing dimensions, not compressing — see the dimensions guide. |
Pick the largest size the form allows
There is no benefit to going smaller than you have to. Every step down in file size is paid for in detail, and the loss is permanent once you save. If a portal says "maximum 100KB", target 100KB — not 50KB "to be safe". The only reason to undershoot is a form that silently rejects files at exactly the limit, which is rare but does happen; 5% under the cap covers it.
Format matters more than the slider
For photographs, save as JPG. JPEG compression is built for continuous-tone images and will reach a small target with far less visible damage than PNG, which is designed for flat colour and sharp edges. A PNG photo forced down to 50KB will look considerably worse than a JPG at the same size.
The reverse is true for screenshots, logos, line art and anything with text: PNG holds the edges crisp, and a JPG at the same size will fringe the lettering with grey speckle.
Crop before you compress
File size is driven by pixel count as much as by compression. A 4000×3000 photo cropped to the subject may land under the cap on its own, with no quality cost at all — because you removed pixels you did not need rather than degrading the ones you kept. If you are far over the limit, resize the dimensions first and compress second.
Why a fixed target is harder than it sounds
JPEG quality settings do not map predictably to file size — the same "quality 70" produces wildly different sizes depending on how much detail the image contains. Hitting an exact KB target means compressing, measuring, adjusting and repeating. The tool does that loop for you and stops just under the number you asked for.
Common questions
Does compressing to a size limit reduce the dimensions?
No. Compression changes how the pixels are stored, not how many there are. The photo keeps its width and height; only the file gets smaller. If you also need specific dimensions, resize separately.
Can I get back the original quality afterwards?
No. JPEG compression discards information permanently. Always keep your original file and compress a copy.
Are my photos uploaded anywhere?
No. Compression runs entirely in your browser — the file never leaves your device, which is also why it works offline once the page has loaded.