Image Resizer
Free online image resizer. Change any photo to exact pixel dimensions in your browser, then download it as a PNG instantly. Fast, private, no signup needed.
About this tool
Need a photo at exact dimensions for a profile picture, a banner, a form upload or a print job? An image resizer changes any picture to the precise pixel width and height you specify, in seconds.
This free tool resizes entirely in your browser and downloads the result as a PNG. Your photos are never uploaded anywhere, so your files never leave your device. No accounts, no watermarks, no waiting.
How to use
Choose your image, then type the exact width and height you want in pixels. Common choices: 800 by 800 for profile pictures, 1920 by 1080 for full-screen banners, or 300 by 300 for thumbnails.
Click Resize Image and download the result instantly. Note that you must enter both dimensions; the tool stretches or squashes the image to fit exactly what you typed, so match your image's proportions if you want to avoid distortion.
The math behind it
Resizing redraws your image onto a new canvas of the target size. When shrinking, the browser averages neighboring pixels together, which keeps the result sharp. When enlarging, it interpolates between pixels, which works but cannot invent detail that was never there.
The output is saved as PNG, a lossless format, so the resized pixels are preserved exactly. That is why resizing down always looks clean, while resizing far up can look soft: information can be removed gracefully, but not created.