Updated October 23, 2026
File size and image dimensions are different
KB and MB measure the encoded file, while pixels measure width and height. A 600 × 600 photo is not necessarily smaller than 100 KB: fine textures and noise need more data than flat backgrounds. A form may impose both a byte limit and minimum dimensions, so check both before changing the image.
Check what the upload limit actually means
This tool uses 1 KB = 1,024 bytes and 1 MB = 1,048,576 bytes. Some forms use decimal limits: “100 KB” can mean 100,000 bytes. If a strict form rejects a result near the limit, try a slightly lower target such as 95 KB. Judge the exported file, not just a rounded label in your file manager.
Choose JPG or WebP for the destination
JPG is commonly accepted for photographs and application forms, but it cannot store transparency: this tool replaces transparent areas with white. WebP can preserve transparency and often works well on modern websites. If a form only accepts JPG, a small WebP will still be rejected. Compressing a PNG here creates a JPG or WebP, not a smaller PNG.
What if an image cannot reach 20 KB?
The tool tries a bounded set of quality and resolution choices. A very detailed or noisy photo may still exceed a small target, and the result then says the target was not reached. Crop unused borders before trying again, or choose a larger limit if permitted. Always check that text, faces and any required details remain legible.
Convert an unsupported HEIC photo first
If your iPhone photo is HEIC and the form accepts only JPG, use the HEIC converter first. Save the JPG, then choose it in the image compressor. There is no automatic file transfer between these tools yet. Converting formats can change file size, so check the compressed result at the end.
A final check before submitting
Confirm the extension and MIME format, file size, width and height, orientation, and readability. If the destination requires a fixed background, exact aspect ratio or a specific face position, compression alone will not meet those rules. Keep the original and submit the processed copy only after reviewing it.
Quick troubleshooting
| Problem | Next step |
|---|---|
| The form says the file is too large | Use a smaller target and inspect the actual bytes. |
| The format is not accepted | Choose JPG if required; convert HEIC first. |
| A transparent background turned white | Choose WebP if the destination accepts it. |
| The image became blurry or too small | Use a larger target or crop unnecessary content before compressing. |