Fixed ratios exist because platforms are picky
Free-hand cropping is fine until the result meets a platform that has opinions. A 1:1 square is what profile pictures and Instagram grids expect. 16:9 is the shape of video thumbnails and slide decks. 4:3 still rules a lot of document layouts and older displays.
Locking the ratio before you drag saves the round trip of cropping, uploading, being told it is the wrong shape, and starting again.
Cropping is not resizing
The two get confused constantly. Cropping cuts away part of the picture — the remaining pixels keep their original detail. Resizing keeps the whole picture and changes how many pixels describe it.
If your image is the right content but the wrong dimensions, resize it. If it contains something you want gone, crop it. Doing both is common: crop first to frame the subject, then resize to hit an exact pixel target.
Frequently asked questions
Is the cropped image the same quality?
Yes. Cropping keeps the original pixels of the area you selected; nothing is rescaled or recompressed beyond the export.
Can I rotate before cropping?
Yes, the rotate button turns the image 90° at a time and the crop selection follows.
What format do I get back?
A PNG, so that any transparency in the original survives the crop.
Does the image leave my computer?
No. It is loaded and cropped entirely in your browser.