How do i properly download ps3 themes?

i downloaded some ps3 themes directly through my ps3, but now i don't know where they are. did they save to my ps3, and if so, where are they? i wanna figure this out before my mom gets home; they may be taking up a lot of space... i guess i just want to be ured that i didn't completely screw up, and that i can re-download them via my computer and a flash drive without unnecessarily taking up more room on my ps3. i mean, if they did save, then i won't do it again... thanks for any advice you can give. (geez, typing on the ps3 is annoyingly difficult for me...)