Image Rotator

Nudge the angle slider by a degree or two until the lines of the document sit level. A rotation that is not a multiple of 90 leaves empty corners, and the tool fills them with the colour you pick — white suits documents best.

Rotating turns the picture about its centre; flipping mirrors it. A horizontal flip puts what was on the right onto the left, which is what you need to correct a selfie-camera shot.

Yes. A positive angle turns the image clockwise, the way every photo app does it.

Rotating by multiples of 90 degrees loses nothing. A free angle has to recompute the pixels, which carries a slight loss that is not usually noticeable.