In short: An image resizer changes an image’s pixel dimensions — by exact width and height or by a percentage — while keeping its aspect ratio if you leave one side on auto.
About Image Resizer
Different places want images at different sizes: 1080 × 1080 for an Instagram post, 1200 × 630 for a link preview, 400 × 400 for a profile photo, or simply “under 2000 pixels wide” for a web form. Resizing to the target size before uploading gives you control over how the image looks instead of leaving it to someone else’s server.
Enter a width, a height, or both. With the aspect ratio locked, leaving one dimension blank calculates it automatically so the image is never stretched. Downscaling uses the browser’s high-quality smoothing, and you can resize a batch of images to the same width in one go.
How to use Image Resizer
- Choose or drop one or more images.
- Pick Pixels and enter a width and/or height, or pick Percentage and enter a scale.
- Keep Keep aspect ratio ticked to avoid distortion, and choose an output format.
- Press Resize, then download each image or all of them as a ZIP.
Examples
Resize ten photos to width 1200 with height on auto; each keeps its own proportions.
Untick aspect ratio and set 400 × 400 only if the image is already square — otherwise crop it to a square first to avoid stretching.
Frequently asked questions
Can I make an image larger?
Yes, but enlarging cannot add detail, so upscaled images look softer.
Does resizing reduce file size?
Usually yes — fewer pixels means less data. For even smaller files, follow up with the Image Compressor.
Is transparency kept?
Yes for PNG and WebP output. JPG does not support transparency, so transparent areas become white.
Are my photos uploaded?
No. Resizing happens in your browser. You can check this yourself: open your browser’s developer tools, switch to the Network tab and use the tool — no request carries your input.
Updated November 2026 · Free, no signup · How we build and test tools