Oh, and FWIW as Steel pointed out, find
is your friend! But you don't even need to know the filename; I found them on my Ubuntu box via:
cd /usr; find . -name '*.jpg'
(going on the assumption that they were most likely in the /usr
hierarchy somewhere, and most likely stored as .jpg
If the world isn't making sense to you, you're either drinking too much or not drinking enough.