Resize image

Resize JPG, PNG, WebP and GIF by pixels or percentage right in your browser — aspect ratio locked, nothing uploaded.

How to resize an image

  1. Drop or pick a JPG, PNG, WebP or GIF file.
  2. Set new pixels or a percentage — aspect ratio stays locked, and it never enlarges by accident.
  3. Resize and download — all on your device.

Why resize images?

Right-sized images load faster and stop your pages shipping pixels no screen will ever show. OptImg resizes with a high-quality Lanczos filter and re-encodes in the same format, entirely on your device — no upload, no queue, no size limit.

Frequently asked questions

Are my images uploaded to a server?
No. Resizing runs entirely in your browser with WebAssembly — your image never leaves your device, and there are no size or file-count limits.
Does resizing keep the aspect ratio?
Yes by default — change the width and the height follows (and vice versa). You can unlock it to set an exact width and height independently.
Will it enlarge a small image?
Only if you ask. “Do not enlarge if smaller” is on by default, so a target larger than the original leaves the image untouched instead of upscaling it blurry.