I, possibly stupidly, bought Persona 4 cause it is on sale. I have been playing it on the PS2 already and I want to know if ill be able to use the save file that I copied onto my PS3 via that PS2 memory card adapter for PS3.

I guess my question is can downloaded PS2 games read saves from an internal PS2 memory card?

should be able to.

Ok cause I have never tried this before and it seems like downloaded PS2 games all use their own clean memory card and not the ones that you would use with a disc based ps1/ps2 game on a PS3.

No, they cannot. They use their own kind of internal virtual memory card. It was the first thing I tested when they put Persona 3 up for download, and I was incredibly disappointed.

oh then nvm then.