PHP files?

I was going through some old files when I stumbled across some PHP files. I know that it holds images, I remember puting them together on a windows program, but for the life of me, I can't figure out how to get the files to open. I've tried downloading stuff off of www.php.net, but I don't know how to work that, or even if its the right stuff to be looking at.

Anyone have any ideas?