Resize images by pixels or percentage
Set a width, a height, exact dimensions or a percentage and resize one or two hundred images in seconds. Aspect ratio is kept unless you choose exact size. Everything runs on your device.
How to use the Image Resizer
- Add images (drag, click or paste).
- Choose how to resize: by width, by height, exact size or percentage.
- Enter the number in pixels or percent.
- Click Resize and download the results (ZIP for many files).
Choosing the right size
Screens are measured in pixels, so the right size depends on where the image will be shown. A full-width blog image is usually 1200–1600 px wide; a social post 1080 px; a thumbnail 300–400 px; an email header 600 px. Making an image bigger than its display size wastes bandwidth and slows the page; making it smaller and letting the browser stretch it looks blurry. Resize to the largest size you actually display.
Keeping the aspect ratio
With "Width" or "Height" the other dimension is calculated automatically so nothing is squashed. "Exact width × height" ignores the ratio and stretches the image to the box you give it; use it only when the source already has the right proportions, or use the crop tool first.
Quality of the result
The tool draws the image onto a canvas with high-quality (bicubic-style) resampling, which is what image editors use for downscaling. Enlarging is possible but cannot add detail; anything over about 150% starts to look soft, which is why "Never enlarge" is on by default.
Format handling
JPG stays JPG (quality 90), PNG stays PNG with transparency intact, WebP stays WebP. HEIC photos from iPhones are decoded on your device and saved as JPG because HEIC cannot be written by browsers. Metadata such as GPS location is not copied into the resized file, which is usually what you want before sharing.
Frequently asked questions
Can I resize many images to the same width at once?
Yes. Add up to 200 images, choose Width and a number, and every image is scaled to that width with its own ratio kept.
Will resizing change the file size?
Yes, roughly in proportion to the pixel count. Halving width and height makes the file about four times smaller.
Does it keep transparency?
PNG and WebP transparency is preserved. JPG has no transparency, so transparent areas become white.
Is anything uploaded?
No. Resizing happens in your browser with the Canvas API; the page works offline once loaded.
Privacy
This tool runs entirely inside your browser using WebAssembly and the Canvas/File APIs. Your files are never uploaded to ToolFlint or any third party; you can verify this in your browser's network tab or by switching to airplane mode after the page loads. Read how we process files.
Last updated 2026-09-23.