Gallery Thumbnail Cropping Issue

There's a weird issue when trying to thumbnail-crop a perfectly square image for gallery submission.
I upload the image, it shows on the screen, and I see the crop marks. However, it's impossible to capture the entire square image within the square of the crop marks. It's as if there's an invisible buffer zone around the edges that are preventing the crop marks from covering the entire square image.
Since my gallery image is square, and the gallery thumbnails are square anyway, it makes no sense to do that, so I'm guessing it's a bug.
! REPORT