Program to make one average of several images - (Apr/21/2012 )

I look to create an average image of, let´s say 10, tissue images; does anyone know a program, preferably for free?

will photoshop layering suit your needs?

if so then maybe acorn ($50 shareware) or gimp (free) will do the job for you (i know acorn uses layers, not sure about gimp but think it does).

gimp does use layers. and as mdfenko said, it's free.

thank you for reply; but I´m not looking for just overlaying images but a calculation program to generate an average image...

imagej should be able to do what you ask with its image calculator.