Question 1

What is 512x512 used for?

Accepted Answer

512×512 is the App icon size, used for app icons and web manifests. Matching it exactly avoids the platform cropping or re-compressing your image in a way you did not choose.

Question 2

How do I resize an image to 512x512 without stretching it?

Accepted Answer

Crop to the right shape first, then scale. Scaling a differently-proportioned image straight to 512×512 distorts it; cropping to 1.00:1 first and then scaling keeps everything in proportion.

Resize to 512 × 512