Kat Von D Keeping Jesse James Tattoo

Kat tells TMZ, "I love my tattoo" -- adding, "It's more than just a portrait, it has a lot of meaning."

FYI -- the tat is a school picture of Jesse ... from when he was in the FIFTH GRADE.

Kat -- whose show "L.A. Ink" premieres tonight on TLC -- also has a tattoo of another ex-BF somewhere on her body ... and she tells us, that's not going anywhere either.