Do the roms erase?

Hi,

I've been loading my Raspberry pi Retropie. I have a 32 GB SD card, but I started loading it with a 4 GB flash drive (I had to prove concept first).

If I delete files off the flash drive to add new ones, do the files I already put on the 32 GB SD card in the Raspberry pi stay on there or are they deleted?

Thanks!
Matt

No, they did not erase. I tried it.