How to Resize Images Without Stretching Them
Aspect ratio explained, with the exact settings that keep people and products looking natural.
Aspect ratio is the relationship between width and height — 4:3, 16:9 and 1:1 are ratios, not sizes. Stretching happens when you change one side without the other.
To resize without stretching, lock the aspect ratio and change only one dimension. The other side follows automatically. This is the default in the UMARIX Image Resizer.
If you need an exact size with a different ratio, you have two honest options: crop (cut off the edges) or pad (add a background border). Stretching is a third option, but it distorts faces and products and should be a deliberate choice, not an accident.
Do not enlarge far beyond the original. Upscaling cannot invent detail; a 500-pixel image shown at 2000 pixels will look soft no matter which tool you use.
For the web, resize to the size the image is actually displayed at. Serving a 4000-pixel photo in a 800-pixel slot wastes bandwidth for every visitor.