How to Compress an Image to a Specific Size (50 KB, 100 KB, 200 KB, 1 MB)

Portals for visas, exams, job applications, ID cards and tax filings store millions of pictures, so they cap each upload at a small size, commonly 50 KB, 100 KB, 200 KB, 500 KB or 1 MB. A modern phone photo is 3 to 8 MB, so it will be rejected as it is.

The good news is that these forms rarely need a big picture. A passport-style photo that fills 600 by 800 pixels looks perfectly sharp at 100 KB.

Three things decide the size of a JPG: the number of pixels, the quality setting and the format. Pixels matter most. A 4000 by 3000 photo has 12 million pixels, while a 1200 by 900 version has about one million, so it is roughly twelve times lighter before any compression is applied.

Quality is the second lever. Dropping from 95 to 75 often cuts the file by more than half with little visible change. The format is the third: a photo saved as PNG can be ten times larger than the same photo as JPG.

The easiest route is a tool that lets you type the size you need. Choose 'To a target file size', enter the number and the unit, and the tool searches for the highest quality that still fits under the limit. If even the lowest sensible quality is too big, it also scales the picture down.

Because it works inside your browser, the photo is never uploaded anywhere, which matters when the picture is an ID or passport photo.

If you prefer to control it yourself, first resize the long side to about 1000 to 1200 pixels. Then export at quality 70 and look at the size. Still too big? Step the quality down by 5 at a time, or shrink the width to 800 pixels. For a 50 KB limit you will usually end up around 600 to 800 pixels at quality 60 to 70.

Always start again from your original file each time. Re-compressing an already compressed JPG throws away detail you cannot get back.

If the form says 'file too small', it also has a minimum size. Raise the quality or the pixel size slightly until you are above the minimum but below the maximum.

If it rejects the format, check whether it wants JPG or JPEG. They are the same thing, only the extension differs. If the form wants exact dimensions, such as 200 by 230 pixels, resize to those pixels first and compress afterward.