How to Compress an Image to Around 100KB

Check the destination form for both file-size and dimension requirements. A 100KB limit alone is not enough if the portal also expects a particular width, height, aspect ratio or format. Treat the published requirements from the destination website as the source of truth.

File size depends on image dimensions, compression settings, format and image complexity. A photo with lots of fine detail can require a different quality setting from a simple graphic even when both have the same dimensions.

If an image is much larger than the form needs, reducing its dimensions is often more useful than aggressively lowering quality. For example, a camera photo may contain millions of pixels even when the destination only displays a small profile image.

Use a crop only when the framing needs to change. Otherwise preserve the aspect ratio and make the smallest dimension change that satisfies the destination requirement.

A target such as 100KB should be treated as a goal, not a promise. After processing, check the generated file's actual size, dimensions and visual quality. Some portals reject files that are only slightly over a limit, so leave a small practical margin when the destination rules allow it.

Always keep the original image. The compressed file is a new delivery copy and should not replace the source you may need later.