simpler maybe !
open all the pix in Photoshop shrink the windows for easier overlook... drag them into a much larger blank background... that you create using edit/new
use ctrl T to resize them all...
use the eraser after clicking on "V" (move) and putting a check mark in the "auto select layer" to trim away whatever is not wanted on each photo (layer)
I also like to change the eraser after after triming out each entry's background to a softer brush (fuzzy) and work all the edges into a better blending condition.
once thats done drag various backgrounds into the photo and use again the ctrl/T to stretch or shrink the background..
for a better blend if you're feeling frisky use image/adjust to use various tools once you click on them (still in auto select on the move (V) tool)
when you have what you want on that large canvas use the marquee tool (M) to select and crop whatever's not wanted
there more to it for better effects but that will get you started... have fun
RonDon
oh there's one here that I made a long time ago... not too proud of it but see how the layers are right ?
http://community.webshots.com/photo/...0646cOQsegRCnF