How to compress an image to 100KB (or any size)
- Drop your image above — or several at once. JPG, PNG and WebP files are accepted.
- Pick the size limit you need. 100KB is selected by default; the list also offers 20KB, 50KB, 200KB, 500KB and 1MB, or choose Custom and type any value from 5 to 20,480 KB.
- Choose the output format: JPEG for photos, or WebP if you need transparency and the form accepts it.
- Check the badge next to each file. A green “under 100 KB” means the target was met; click Download (or Download all).
Why do uploads demand “under 100KB”?
Government portals, visa applications, job sites, school forms and older CMS systems often enforce strict file-size limits — commonly 20KB, 50KB, 100KB or 200KB — to keep storage and bandwidth predictable. A modern phone photo is typically 3–8 MB, which is 30–80× over the limit, so simply re-saving it is not enough.
How the tool hits the target
Instead of asking you to guess a quality number, the tool tests for you. It encodes your image at the original dimensions and runs an eight-step search between 5% and 95% quality, keeping the highest quality whose file still fits under the limit. If even 5% quality is too large, it shrinks the pixel dimensions (each pass scales by roughly the square root of the size ratio, with a safety margin) and searches again, up to five passes. It stops reducing once either side would fall to 150 pixels or less. If the target is still out of reach you receive the smallest file it could produce, labelled “best effort” with its real size, so you are never told a file fits when it does not.
What to expect at common limits
- 200KB and above: a typical phone photo keeps most of its resolution and looks nearly untouched.
- 100KB: fine for a passport-style portrait or a document photo; large landscapes will be scaled down to roughly screen size.
- 50KB and 20KB: expect visible softness and smaller pixel dimensions. These limits suit a face crop, signature or thumbnail, not a wide scene.
Practical tips
- Crop first for tiny limits. A tight crop of the face or document needs far fewer bytes than a wide shot. Use the Image Cropper, then compress.
- Flat backgrounds compress best. Plain walls shrink well; busy textures, grass and noise eat the budget.
- JPEG has no transparency. Transparent areas of a PNG are filled with white when you choose JPEG. Choose WebP to keep them, if the upload form accepts WebP.
- KB means 1,024 bytes here. A 100 KB target is 102,400 bytes, which matches how Windows reports file size. macOS counts 1 KB as 1,000 bytes, and a portal that does the same is slightly stricter, so leave a small margin if the file lands very close to the limit.
- The output is always JPEG or WebP. If a form insists on PNG or a particular pixel size, resize with the Image Resizer and check the form's accepted formats first.
- Metadata is dropped. The image is redrawn and saved fresh, so camera details and GPS coordinates in the original are not carried over.
Is it private and safe?
Yes — and for this tool that matters more than usual, because size-limited uploads are often ID photos, passports and application documents. All processing happens inside your browser on your own device. Your images are never uploaded to any server, so nothing can be stored, seen or leaked.
Related guides
A longer walkthrough with before-and-after expectations is in How to compress an image to 100KB. To understand why quality and dimensions trade off the way they do, read Image dimensions vs file size and Lossy vs lossless image compression. If you do not need an exact limit, the general Image Compressor is quicker.
Frequently asked questions
Will my image still look good at 100KB?
Usually yes for a portrait or document photo. The tool looks for the highest quality that fits and only reduces pixel dimensions when quality alone cannot reach the limit, so a large phone photo may come out noticeably smaller in pixels but still clean.
What if the target can't be reached?
The tool steps down quality and then dimensions for up to five passes, and stops before an image gets smaller than about 150 pixels on a side. If it still cannot fit, you get the smallest file it managed, marked as best effort with its actual size.
Can I compress to 50KB or 20KB too?
Yes. Pick 20KB, 50KB, 200KB, 500KB or 1MB from the list, or select Custom and enter any size from 5 to 20,480 KB. Very small targets work best on tightly cropped subjects.
Why is my file a little below the target instead of exactly 100KB?
The search tries eight quality levels and keeps the best one that fits, so the result lands just under the limit rather than exactly on it. That is intentional, since a file even one byte over would be rejected by the form.
Should I choose JPEG or WebP?
Choose JPEG when the upload form says JPG or JPEG, which is the safest option for government and job portals. WebP gives smaller files and keeps transparency, but some older systems refuse to accept it.
Does this change the photo's dimensions?
Only when needed. If the target can be met at the original pixel size, the dimensions stay the same and only quality drops. Otherwise the image is scaled down proportionally, so the aspect ratio never changes.
Do you store my images?
Never. Files stay on your device and are processed in the browser, which makes the tool safe for passport and ID photos. There is no watermark, sign-up or limit on how many files you process.