Choosing the right shape
Square (1:1) suits profile pictures and Instagram posts. 4:5 is the tallest portrait Instagram allows in the feed. 16:9 matches YouTube thumbnails, presentations and most screens, while 9:16 is the full-screen shape used by Stories, Reels, Shorts and TikTok. 4:3 and 3:2 are the shapes most cameras and phones shoot in, handy when you want to straighten a composition without changing its proportions.
Free lets you draw any rectangle, which is useful for cutting a signature, a receipt or a single item out of a bigger photo.
Tips for a better crop
The faint grid splits the box into thirds. Placing the subject's eyes or the horizon along one of those lines usually looks more balanced than putting it dead centre. Leave a little space in front of a face or a moving object so it has room to look or move into.
Cropping keeps the original resolution of the area you select, so the result is as sharp as the photo you started with. If you also need a specific pixel size, resize the cropped image afterwards.
Keyboard and accessibility
You can crop without a mouse. Tab to the crop area, use the arrow keys to move it and hold Shift with the arrow keys to make it bigger or smaller. The size of the result in pixels is shown below the image the whole time.