TARGET SIZE IN KB · PIXELS OR CM · NO UPLOAD
Compress an Image to an Exact Size in KB
Application portals often reject a photo that is a few kilobytes too big. Pick the limit, such as 100 KB, and get a file just under it, at the best quality that still fits.
Pick a size such as 100 KB, 50 KB or 20 KB, then choose your photo or signature.
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How to compress an image to a size in KB
Pick the size limit
Choose Under 200 KB, 100 KB, 50 KB or 20 KB, or type the exact limit your form gives. If the form also names a size in pixels or centimeters, set that too.
Open the photo or scan
Drop the picture on the page or tap Open image. Your phone’s photo library and camera both work. The result shows its final size in KB and its pixel size.
Save and upload it
Save the file and upload it to the form. If the smallest possible file is still over the limit, the page says so and suggests a smaller pixel size instead of guessing.
FEATURES
What this page does
Hits the limit you set
A search tries up to seven quality levels and keeps the best one under your limit. If quality alone can’t get there, it shrinks the pixel size in small steps.
Honest when a size is impossible
Instead of a broken file, you get a plain answer, for example the smallest it could make at the current width, and a smaller width to try.
Pixels or centimeters
Forms that ask for a print size, such as 3.5 × 4.5 cm at 300 DPI, get the matching pixel size: 413 × 531.
Photos and signatures
A signature on white paper compresses very differently from a portrait. Both work, and a scan with a lot of empty white is often the easiest to fit under 20 KB.
What a “100 KB” limit really means
A kilobyte is 1,000 bytes to some systems and 1,024 bytes to others, and forms rarely say which they use. The difference is small, but a file of 101,000 bytes passes one check and fails the other. This page starts from a target of 100,000 bytes, which is under the limit either way.
File size and pixel size are separate rules. A form may ask for “under 50 KB” and also “200 × 230 pixels”. Set both here and they are applied together: the photo is resized first, then compressed to fit the limit. Doing it in that order keeps more detail than squeezing a large photo down to a tiny file.
Centimeters, inches and DPI
A size in centimeters only becomes pixels once you know the DPI (dots per inch). The math is pixels = centimeters ÷ 2.54 × DPI. A passport-style 3.5 × 4.5 cm photo at 300 DPI is 413 × 531 pixels; at 200 DPI it is 276 × 354.
The DPI number stored inside a file doesn’t change how the image looks on screen or how big the file is. Only the pixel count does. If a form checks DPI, it usually means the pixel size that DPI implies.
| Print size | 200 DPI | 300 DPI |
|---|---|---|
| 3.5 × 4.5 cm | 276 × 354 px | 413 × 531 px |
| 2 × 2 in | 400 × 400 px | 600 × 600 px |
| 5 × 5 cm | 394 × 394 px | 591 × 591 px |
Getting a small file that still looks right
When a limit is very tight, a few things help more than lowering the quality further:
- Crop away background first. Fewer pixels of wall or desk leave more of the budget for the face.
- Save photos and scans as JPG. The file keeps its own format unless you pick another, and most forms ask for JPG.
- For a signature, a plain white background compresses far better than a gray, shadowed photo of paper.
- Don’t enlarge a small photo to meet a pixel size. It adds file size without adding detail.
Is it really private?
Forms that want a photo under 50 KB are often for identity documents, exams, visas or job applications. Those pictures are exactly the kind you shouldn’t hand to a server you know nothing about. Here the photo is resized and compressed inside your browser tab and saved straight to your device.
The location stored in a phone photo is removed when the file is re-encoded, which every size target does.
You don't have to take our word for it. Three checks:
- Open your browser's developer tools, choose the Network tab, then open and save an image. No request carries your file.
- Open an image here once, then turn on airplane mode and run the same job again. It still works, because nothing needs a server.
- Read the page's response headers: its Content-Security-Policy lets it connect only to this site itself, so there is no outside host a file could go to.
Reference
| Targets | Under 1 MB, 500 KB, 200 KB, 100 KB, 50 KB, 20 KB or a custom size |
|---|---|
| Search | Up to 7 quality steps, then smaller pixel sizes in 15% steps |
| Saves | The same format by default; JPG, PNG or WebP if the form needs another |
| Sizes | Pixels, a longest side, a percentage, or centimeters and inches at a DPI |
| Metadata | Removed, GPS location included |
| Browsers | Chrome, Edge, Firefox and Safari, including on phones |
Frequently asked questions
How do I reduce a photo to under 100 KB?
Choose Under 100 KB, then open the photo. Image Studio tries several quality levels and keeps the best one under the limit. If it still can’t fit, it shrinks the pixel size a little at a time and tells you the size it used.
Why does my file come out at 98 KB and not exactly 100 KB?
Compression can’t land on an exact byte count, so the target is a ceiling, not a goal. Being a little under means the file passes the check whether the form counts a KB as 1,000 or 1,024 bytes.
Can I compress a signature to 20 KB?
Usually, yes. Scan or photograph the signature on plain white paper, crop close around it and pick Under 20 KB. Text and lines stay readable at small sizes when the background is clean.
The form wants 200 × 230 pixels as well. Can I do both?
Yes. Set the pixel size in More options and the size limit with the chips. The photo is resized first and compressed second, in one pass, so you only lose quality once.
What if the form asks for a size in cm?
Switch the size to centimeters and enter the DPI the form gives, often 200 or 300. The page shows the pixel size that results, for example 413 × 531 pixels for 3.5 × 4.5 cm at 300 DPI.
Why was my photo rejected even though it is under the limit?
Forms often check more than size: the file type (usually JPG), the pixel dimensions, and sometimes the face position or background. Check the form’s full instructions; this tool handles the file type, size and pixels.
Will the photo still look sharp?
At 100 KB a portrait usually looks fine on screen. At 20 KB expect some softness. The compare view lets you zoom in and check before you save, and cropping away background helps more than anything else.