How to Compress an Image to 100 KB, 1 MB or Any Size
Job portals, visa applications and marketplaces often reject photos over a size limit such as 100 KB or 2 MB. There are only two levers that matter: the number of pixels and the encoder quality. Use them in the right order and you rarely need to guess.
The two levers
- Pixel dimensions. A 4000 × 3000 photo has 12 million pixels; at 1600 × 1200 it has under 2 million. File size falls roughly with the number of pixels, so halving both width and height cuts the data to about a quarter.
- Quality. JPEG and WebP throw away detail your eye is unlikely to notice. Going from quality 95 to 80 often shrinks a photo a lot with little visible change; going far below 60 starts to show blocky artefacts.
Rule of thumb: if a photo needs to shrink by more than about half, reduce the dimensions first. Pushing quality alone that far makes it look worse than a smaller, cleaner image.
Step by step
- Check what the form actually needs: maximum size (KB or MB), format (usually JPG), and sometimes exact pixel dimensions.
- If pixel dimensions are given, resize or crop to them first.
- Open Compress Image, choose Target size and pick the limit (e.g. 100 KB).
- If the tool says the target cannot be reached even at the lowest quality, also choose Limit dimensions (for example 1280 px) and run it again.
- Check the result at 100% zoom before uploading — faces and text are where artefacts show first.
How the target-size mode works
Our compressor tries up to eight quality levels per image in a binary search and keeps the highest quality that fits under your limit. It never upscales and never uploads the image: your browser’s own JPEG/WebP encoder does the work.
Typical sizes
| Use | Common limit | Sensible dimensions |
|---|---|---|
| Passport-style or profile photo for a form | 20–200 KB | 600 × 600 to 800 × 1000 px |
| Email attachment | 1–5 MB per message | 1600–2048 px on the long side |
| Website hero or blog image | as small as looks good | the largest size it is displayed at (×2 for sharp screens) |
Which format?
Use JPG for photos when a form requires it. PNG is lossless and is usually much larger for photos; it is right for screenshots, logos and images with transparency. WebP gives smaller files than JPG at similar quality and is supported by current browsers, but some upload forms still refuse it. See JPG vs PNG vs WebP.