Cut covers on songs

hello guys, how are you?
I know that images can be imported and exported, in the same way I know that you can "correct their aspect ratio" for each song, my question here is, can the covers be cropped? For example, I have a song that has a cover 1000x600, I want to change it to 600x600, is there that option or does it have to be done manually?

What do you mean by "manually"?
Did you have a look at "Adjust Cover" after a right mouse click on the cover field in the tag panel?

Or if you prefer an action:

You have to do that outside Mp3tag, manually.

From the linked help documentation:

Max. Size is the maximum width and height in pixels of the embedded cover image. If the cover is smaller than the size provided, the size of the cover is not changed. Resizing the image keeps the aspect ratio.

In Mp3tag you can reduce only both pixel sizes at once - the width and the height - but not cropping the image.