Free — no sign-up
Image Resizer
Resize an image to the shape you need, without uploading it.
Runs entirely in your browser. Nothing you enter is sent to MASK.
PNG, JPEG or WebP, up to 20 MB. You can also drop a file onto this panel.
Enlarging is off by default: making an image bigger invents pixels, so the result is softer and the file is heavier.
Fill: you get the exact size, and the middle of the image is kept.
Questions
- Is my image uploaded anywhere?
- No. Your browser reads the file, decodes it, draws it and writes the new one, and the download comes out of this tab's own memory. The page makes no network request with your image at all — you can disconnect from the internet once the page has loaded and the tool still works.
- Why will it not open my SVG?
- An SVG is not really a picture, it is a small document that can carry scripts and references to other servers. Drawing one to a canvas means running it, so this tool refuses SVG entirely and accepts PNG, JPEG and WebP.
- What is the difference between fill and fit?
- Fill gives you exactly the pixel size you asked for and crops whatever does not fit, keeping the middle of the image. Fit never crops: it shrinks the whole image until it sits inside the box, so one side usually ends up smaller than the number you typed. Nothing is ever padded out with bars.
- Are the preset sizes still correct?
- The ratios are stable; the pixel figures may not be. They were read from Meta's ads guide and the Open Graph sharing documentation on 15 August 2026, and those pages carry no revision date, so treat the pixels as a sensible default rather than a rule. You can type any size you like instead.
- Why are there size limits?
- Because the work happens in your tab rather than on a server. 20 MB is the largest file that is comfortable to decode, and an image over 50 megapixels is refused however small the file is: a huge image of flat colour compresses to almost nothing and then asks for tens of gigabytes of memory the moment it is decoded.
- Why did my transparent PNG come out with a white background?
- Because you chose JPEG, which has no transparency at all. Anything see-through is filled with white before the JPEG is written, which is kinder than the black most encoders would give you. Choose PNG or WebP to keep transparency.