A square 512 x 512 image - an app icon or a high-resolution avatar. Upload your picture below and download it at exactly this size.
Tip: start from the largest original you have - enlarging a small picture to 512 x 512 will look soft.
Choose your picture, check that width is 512 and height is 512, pick how it should fit (crop, fit inside, or stretch), and click Resize. Then download the result.
It is commonly used for an app icon or a high-resolution avatar. Platforms change their guidelines from time to time, so check the current recommended size if an upload looks wrong.
Not unless you choose Stretch. "Fill & crop" scales the picture to cover the 512 x 512 area and trims the overflow; "Fit inside" keeps the whole picture and adds a background colour.
No. Everything runs in your browser, so your photo stays on your device.
After resizing, run the file through the compress tool to bring it under a size limit such as 50 KB or 200 KB.