Thanks, all, for the responses. I understand about sizing and dpi.
Suppose I have a 300 dpi JPEG that measures 6.97 inches x 4.15 inches. To make a 4x6, I'd leave the 4.15 dimension as is, but I'd want to crop the 6.97-inch side more precisely, evenly on both sides, to 6.4 inches. What's the best way to do that in Paint?
Thanks.