Two numbers that are easy to confuse
Almost every rejected upload comes down to mixing up dimensions and file size. Dimensions describe the grid of pixels, written as width by height. File size describes how many bytes those pixels take up once the format has compressed them.
They move independently. Compressing an image harder reduces the file size while leaving the dimensions untouched. Shrinking the dimensions reduces both. This is why a form can accept your 40KB photograph and still reject it for being the wrong shape.
Checking before you upload
It takes a few seconds to confirm both numbers, and it saves the far longer process of discovering a problem after submission. Read the form instructions, note the required dimensions and the KB range, then check your file against both.
Pay particular attention to the lower bound. Portals that specify a range such as 10 to 20 KB reject anything under it, and an over compressed file is just as invalid as an oversized one.
What the aspect ratio tells you
The ratio is the width divided by the height. A square image gives 1.000, a standard photograph around 1.333, and a passport style portrait about 0.778. If your ratio does not match what a form expects, resizing to its dimensions will stretch the picture, so crop to the right shape first.
Frequently asked questions
Why does my phone show a different file size?
Some systems count a kilobyte as 1000 bytes and others as 1024. The underlying file is identical, but the number shown differs slightly depending on which convention is used.
What is the difference between file size and dimensions?
Dimensions are how many pixels wide and tall the image is. File size is how much storage those pixels occupy once compressed. Two images with identical dimensions can have very different file sizes.
Which one does my form care about?
Usually both. Portals typically specify pixel dimensions and a KB range separately, and an image that meets one but not the other is still rejected.
What does megapixels mean?
It is the total pixel count divided by a million. A 4000 by 3000 image contains twelve million pixels, so twelve megapixels. It describes how much detail was captured, not how large the file is.
Does this show camera and location data?
No. The tool reads only what the browser exposes about the file and the decoded image, which does not include EXIF fields such as camera model or GPS coordinates.
Is my image uploaded to check it?
No. Everything shown here is read from the file on your own device. Nothing is transmitted anywhere.