If these 2 images are jpgs/gifs/pngs or any other pixel image format, you may want to try an image editor, not a vector graphics program like Inkscape. The GNU Image Manipulation Program (GIMP) is the preferred free image editor, millions of people use it -
http://www.gimp.orgOr are the two images in vector formats like ai, eps, or svg?
That doesn't mean you should stop learning how to use Inkscape, this is a great program too, just not for editing pixels
