Image Resizer: Complete Usage Guide
Set exact pixel dimensions for web, social or print — the biggest single win for page speed.
Open the toolPurpose
The Image Resizer changes the pixel dimensions of an image. It is the most effective optimisation available because the saving is quadratic: halving width and height removes 75% of the pixels before any compression runs. It also matters for platforms that require exact dimensions — social banners, avatars, marketplace listings and ad slots all reject or crop images that are the wrong size.
How to use it
- 1Upload your image.
- 2Enter the target width. Keep 'maintain aspect ratio' on so the height follows automatically.
- 3Turn the ratio lock off only if you deliberately need a fixed frame — otherwise the image will distort.
- 4Check the preview, then download the resized file.
Tips & tricks
- Common targets: 2560px for full-width heroes, 1600px for blog images, 800px for cards, 400px for avatars.
- Never upscale. Enlarging a small image invents pixels and looks soft; go back to the original source instead.
- Resize first, compress second. Doing it in the other order wastes work and quality.
- For a fixed frame like a square thumbnail, crop with the Image Cropper rather than distorting the aspect ratio.
- Set explicit width and height attributes in your HTML so the browser reserves space and the layout does not jump.
Common errors and fixes
The image looks stretched
Aspect ratio lock was off. Re-run with it on, or crop to the target ratio first.
The resized image looks soft
You upscaled beyond the original resolution. Resizing cannot add detail that was never captured.
Transparency disappeared
Export as PNG or WebP. JPG has no alpha channel and fills transparent areas with white.