IMAGE SIZE GUIDE
KB versus pixels: two different image sizes.
A form can ask for both a file smaller than 50 KB and an image that is 200 × 230 pixels. Those requirements measure different things, so you need to check both.
| Measurement | What it tells you | Example |
|---|---|---|
| KB or MB | The size of the saved file in bytes | Maximum 50 KB |
| Pixels (px) | The number of image pixels across and down | 200 px wide × 230 px high |
| Aspect ratio | The relationship between width and height | 200:230 simplifies to 20:23 |
| DPI or PPI | A physical scanning or printing density | 300 pixels per printed inch |
Why equal dimensions can produce different KB
A photo of fine hair, foliage or a textured background generally needs more image data than a simple signature on white paper. JPG quality settings and the file format also affect the saved size. Two images can both be 200 × 230 pixels and still have different byte counts.
There is no fixed conversion from pixels to KB. Setting 200 × 230 pixels does not automatically create a 50 KB file. To meet both requirements, resize the dimensions and then check the size of the encoded output.
A worked example
Imagine a form asks for a JPG with a maximum size of 50 KB and dimensions of 200 × 230 pixels. In PhotoSizeKit, set Maximum to 50, Width to 200 and Height to 230. Leave Minimum at 0 unless the form also gives a lower limit.
A result measuring 34,500 bytes and 200 × 230 pixels would meet those two settings. That is 34.5 KB using this tool’s decimal units. This is an example calculation, not a promise that every source image will produce that size.
If the original is a different shape, choose whether to keep the entire image with white padding or crop it to fill the rectangle. Neither option changes your requested output width and height.
KB, KiB and rounding
PhotoSizeKit uses 1 KB = 1,000 bytes and 1 MB = 1,000,000 bytes. A kibibyte (KiB) is 1,024 bytes. File managers may display sizes using different units or rounding, so the displayed number can differ even when the file itself has not changed. The result panel includes the exact byte count.
If a portal says “less than 20 KB” rather than “20 KB or less,” choose a slightly lower maximum, such as 19.9 KB. Follow any exact byte limit stated by the portal.
What about centimetres and DPI?
For physical output, pixels = inches × pixels per inch, and inches = centimetres ÷ 2.54. If a form gives both a physical size and a resolution, you can use that relationship to calculate approximate pixel dimensions, allowing for rounding.
This tool sets pixel dimensions; it does not provide a control for a specific DPI metadata value. If a portal requires an embedded DPI setting, use software that can explicitly set and verify that metadata.
A quick checklist for application images
- Read the permitted output format: JPG, PNG or another format.
- Check the minimum and maximum file size, including any exact byte limit.
- Check the width and height separately, in the units the form specifies.
- Follow the rules for background, framing and image age.
- Open the downloaded file and confirm it is still clear before submitting.