Image size: KB, MB and pixels explained
A file-size limit controls how many bytes an upload accepts. A dimension limit controls the width and height of the image. Meeting one does not automatically satisfy the other.
Common limits
| Limit | Bytes used by this tool |
|---|---|
| 100 KB | 100,000 |
| 300 KB | 300,000 |
| 1 MB | 1,000,000 |
| 3,000 KB | 3,000,000 |
Some software uses binary units or labels them inconsistently. A KiB is 1,024 bytes and a MiB is 1,048,576 bytes. The output byte count is the reliable comparison when a form has a strict limit.
Prepare a photo for an upload form
- Read the form requirements: accepted format, maximum bytes, dimensions and any minimum size.
- Use pixel resizing if dimensions are specified.
- Use the compressor for a maximum file size. Inspect the final dimensions because they may change.
- Open the result and check small text, faces and edges before submitting.
This tool does not guarantee compliance with any particular government, exam or identity-document portal. It does not crop to an aspect ratio or guarantee a minimum byte size.
Why a tiny limit can look blurry
Large, detailed images need more encoded data. To fit a smaller budget, lossy encoding can remove detail and the compressor may reduce dimensions. Try JPG for a photo or a less restrictive size limit when text becomes hard to read.