No crop photo at any size you type
Type a width and a height in pixels. This page opens on 1080 x 1080 pixels.
Your photo never leaves this device. To check, open your browser's developer tools, choose Network, and export a photo: no request carries it.
Custom lets you type the width and height of the frame yourself, in pixels. It opens on 1080 x 1080, and the ratio in lowest terms, such as 3:2, updates next to the fields as you type.
Each side can be any whole number from 16 to 4096. If a value is not allowed, a message beside the field says what is wrong and the last good size stays in place.
Use it for a size the five ready-made frames do not cover: a print at a fixed pixel count, a banner with an unusual shape, or a thumbnail that must be a certain size. Your photo, its Size and its position carry over when you change frame, and the photo is fitted again to the new shape.
The export has exactly the pixels you typed, as a JPEG or a PNG, with no metadata. Large frames take longer to export than small ones because more pixels are drawn.