Pixel Bench

Why upload forms reject your photo

The limit says 2 MB. Your file says 2 MB. It still gets rejected. Here is what is actually being measured, and how to land under a limit reliably rather than by guessing.

A megabyte is two different numbers

This is the single most common reason a file that looks small enough gets refused. There are two definitions of "MB" in everyday use, and they differ by about 5%:

So a file Windows reports as "2.00 MB" is 2,097,152 bytes. If the upload form means the decimal 2,000,000, your file is 97,152 bytes over and gets rejected — while your own computer insists it is exactly 2 MB. Nothing is broken. The two are measuring different things.

The practical rule: aim about 5% under whatever number you were given. If the form says 2 MB, target 1.9 MB and the ambiguity stops mattering. That is why the compressor here reads KB as 1,000 bytes — if the form meant 1,024, you are safely under either way, whereas the opposite reading overshoots.

Why phone photos are so large

A current phone camera produces images around 4,000 by 3,000 pixels — 12 million pixels per shot. Even with efficient compression that lands between 3 MB and 8 MB, and portrait mode, HDR and RAW capture push it higher.

The limits you are being asked to meet were mostly written years ago, sized for scans and digital cameras of the time, and have not moved. A 500 KB limit was generous in 2010 and is roughly one-tenth of a modern phone photo. You are not doing anything wrong; the gap is real and it is widening.

The limits you will actually meet

Two different limits, often confused

A form may restrict file size in bytes, dimensions in pixels, or both, and they are not the same thing. "Maximum 600 by 600 pixels" is a dimension limit; a 600 by 600 image can still be a large file if it is stored losslessly. "Maximum 200 KB" is a size limit that says nothing about dimensions.

If a form rejects your image without explaining why, check whether it stated a pixel limit you missed. It is a common cause of a file that is comfortably under the byte limit still being refused.

How to get under a limit without wrecking the picture

  1. Reduce quality before you reduce pixels. At normal viewing sizes, a quality reduction is far less noticeable than a resolution reduction. Dropping a JPEG from maximum to around 70% quality typically halves the file with no visible difference.
  2. Only then reduce dimensions. If quality alone cannot reach the target, scale the image down. A photo intended for a 600-pixel-wide box on a web page gains nothing from being 4,000 pixels wide.
  3. Send JPEG unless told otherwise. WebP is smaller, and plenty of older portals reject it outright. If the form names a format, use that one exactly.
  4. Always work from the original. Compressing an already-compressed copy stacks the damage. Go back to the file the camera produced.

The compress-to-a-size tool does the first two steps in that order automatically: it searches for the highest quality that still fits your budget, and only reduces dimensions when no quality setting can get there.

When the file still will not go under

Occasionally a limit is genuinely unreachable for the image — a detailed photograph forced under 20 KB, for example. At that point something has to give, and it is better to know than to keep trying:

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