software i'm looking for

i am on the hunt for a command line program that takes an image file in one of the major image formats (at least gif, jpg, and png) and draws a straight line in it, vertical or horizontal, at the specified position, in the specified color. or as an alternative, one that draws a rectangular box at a specified position and size in a specified color. i need to do this as part of an automated script so i need to find one that is totally non-interactive.