The four things these forms check
Almost every rejection comes down to one of four constraints, and they are checked independently — passing three and failing one still fails:
- File size in bytes. "Maximum 500 KB". The most common limit and the easiest to fix.
- Pixel dimensions. "Between 600 × 600 and 1200 × 1200". Compression does nothing for this — only resizing does.
- File format. Usually JPEG, sometimes JPEG or PNG. WebP and HEIC are almost universally rejected.
- Aspect ratio or physical size. Mostly on ID and visa photos — "35 × 45 mm", "square", "head must occupy 70–80% of the frame".
The error message often names only the first one it hit, which is why fixing the size and resubmitting sometimes produces a fresh complaint about dimensions.
Satisfy them in this order
The order matters, because fixing them in the wrong sequence means redoing work:
- Format first. If the file is HEIC from an iPhone or WebP saved from a website, convert it before anything else. Everything downstream assumes a format the portal will read. HEIC to JPG · WebP to JPG
- Crop and aspect ratio next, if the form specifies them. Cropping changes the pixel count, so doing it after resizing wastes the resizing.
- Dimensions third, if there is a pixel limit.
- File size last. Compression is the only step that does not change what the image contains, so it belongs at the end.
Aim under the stated limit, not at it
"KB" is genuinely ambiguous — Windows treats 1 KB as 1,024 bytes, macOS as 1,000, and the form's developer picked one without telling you. A file your computer calls exactly 500 KB can be 512,000 bytes and fail a 500,000-byte check.
Target about 5% under whatever number you were given and the ambiguity stops mattering. The compressor here reads KB as 1,000 bytes for exactly this reason: if the form meant 1,024, you are safely under either way, whereas the opposite reading overshoots a 1,000-based limit and gets rejected at the door.
Limits you will meet in practice
- Visa and immigration portals: 100–300 KB, often JPEG-only, usually with pixel dimensions specified too. The tightest limits anywhere.
- Job applications and CV portals: 1–5 MB, but the limit frequently covers your entire application — CV, cover letter and photo together — not each file.
- Government services: 200 KB – 2 MB, and often a strict format list.
- University applications: 1–2 MB, commonly with a square crop for the photo.
When the limit is genuinely unreachable
Occasionally a detailed photograph simply cannot reach a very tight limit at usable quality. Before accepting a badly degraded image:
- Crop rather than scale. Removing empty background keeps the subject at full detail while cutting the pixel count. On a portrait this is usually the best move available.
- Check whether a different format is allowed. If PNG is permitted and the image is a scanned document rather than a photograph, PNG may be both smaller and sharper.
- Look for a separate upload slot. Some portals have a higher limit for "supporting documents" than for "profile photo".
- Take a new photo against a plain background. A plain wall compresses dramatically better than a cluttered room — the same camera and the same limit can produce a visibly better result purely because there is less detail to encode.
Two things worth knowing before you upload
Metadata does not survive. Any tool that decodes and re-encodes an image produces a new file from the pixels alone, so GPS coordinates and timestamps are dropped. For an application upload that is a privacy improvement — the portal receives your photo, not your home address. More on what photos carry.
Keep the original. Applications get resubmitted, and portals change their rules. Compress a copy every time rather than compounding the damage by re-compressing a file you already compressed last month. Each pass costs you something permanent.