You can't copy and paste them because it's mostely .img files with files inside them, you use SparkIV to open up those images.
btw.. you did browse through all the clothing ingame right? Because you're probably only replacing a selection of items, doesn't mean you'll have them on if you launch the game.
It's easiest to check with simple native trainer (you can browse through all the available clothing and accessories through it) but you can also just visit all the clothing stores and check all the clothing. Just keep in mind that the modded textures won't show up modded on the clothingracks, you'll have to actually try them on to see if they're different.