Hi and welcome to bfmods.com
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1)The background picture is a move, and it's stored in \mods\bf1942\movies.
You'd have to exchange it for another .bik file. It's no problem, really, just download "bink and smacker" (free) and convert your image or video to .bik format.
2) You can work with GMax, the freeware offspin of 3ds Max. However, this has VERY limited support for advanced modeling and to be honest, it simply is a huge pain in the ass if you want to achieve really good models. For getting to know 3d modeling and rendering it is absolutely fine, though.