What this tool does
Choose an image and you will see its original dimensions. Set a new width or height, or use a scale preset (25%, 50%, 75% or 100%), and the output dimensions and scale factor update. With Lock Aspect Ratio on, changing one number changes the other so the picture isn’t stretched.
How to use it
- Choose a JPG, PNG, WebP or AVIF image, or drop it on the page.
- Type a width or height, or press a scale preset. Leave Lock Aspect Ratio on unless you want to change the proportions.
- Press Resize Image.
- Press Download Resized Image. The file name includes the new size.
Why resizing matters more than compression
An image’s pixel size has a bigger effect on file size than any quality slider. A photo that is 4,000 pixels wide but shown in an 800 pixel column makes visitors download many times more data than they use. A good routine for a site:
- Work out the largest size the image is shown at, and double it for high-density screens.
- Resize to that width.
- Then compress or convert with the Image Compressor or a format converter.
Options and behaviour
- Aspect ratio lock keeps proportions. With it off, you can set any width and height and the image is stretched to fit.
- The output keeps the input’s format. JPG, WebP and AVIF are lossy, and the tool saves them at a fixed quality of 92% (there is no quality control here). PNG stays lossless.
- Enlarging is possible, because you can type any size, but it adds no detail, only blur. The largest side is capped at 8,192 pixels.
- Transparency is kept in PNG, WebP and AVIF.
Where it runs
The resize happens in your browser, so the image isn’t uploaded. AVIF files are the exception: browsers can’t write AVIF, so an AVIF is resized on the server with PHP’s GD library, which needs AVIF support in the server’s build. The file is kept temporarily for the download.
Limits
- Metadata such as EXIF and colour profiles is not carried over. Browsers apply EXIF rotation when they open a photo.
- One image at a time. The page states a 20 MB maximum but doesn’t check it in the browser.
- Animated images become a single still frame.
If you need a particular shape instead of a particular size, use the Image Cropper.
Does resizing reduce quality?
Making an image smaller is mostly fine. JPG, WebP and AVIF are re-encoded at 92%, so keep your original file.
What happens if I unlock the aspect ratio?
You can set width and height independently, which stretches the picture if they don’t match the original proportions.
Does it keep the file format?
Yes. The output uses the same format as the input.
What is the largest size I can make?
The longest side is capped at 8,192 pixels.
Is my image uploaded?
No for JPG, PNG and WebP, which are resized in your browser. AVIF files are resized on the server, so they are uploaded temporarily.