Resize a folder of images at once
By pixels, by percentage, or to fit inside a box. Every pixel thrown away is averaged into the ones that stay, by a Lanczos filter rather than the browser’s own redraw — which is the difference between a crisp thumbnail and a jagged one.
- Nothing is uploaded
- No signup
- Free, with no paid tier
- Works offline after the first visit
Questions
How do I resize without stretching the image?
Leave one of the two boxes empty. Give a width, or a height, or a box to fit inside, and the other side follows from the picture’s own proportions. There is no ratio lock to switch on or off: the number you do not type is what keeps the shape. Filling in both a width and a height is how you ask for a stretch, and the page says so before the run when you have.
Why do resized images sometimes come out jagged?
Because the usual one-step redraw reads about one source pixel in ten on the way to a tenth of the size and ignores the rest, which is what leaves stair-stepped edges and shimmering detail. Every pixel dropped here is averaged into the ones that remain, by a Lanczos-3 filter widened to the scale factor. Measured against Pillow’s LANCZOS on a zone plate shrunk ten times, that is an RMSE of 0.70 where a one-step bilinear redraw is 20.8, and 0 is identical.
Can I make an image bigger?
You can scale up, but nothing is invented: an enlarged photo is the same detail spread over more pixels, so it looks softer than the original. There is no AI upscaling here.
Does it resize a whole folder in one go?
Yes. The setting you choose is applied to every image in the batch, and the results come back as a single zip.