Other than the one free image they give you with each auction (I try to make the one picture work when possible), you can always try photobucket.com. I've never used it myself, but it appears to be free and I've seen several people using it. There's also one called tinypic.com and a few others. Maybe someone that uses one of the free services can give you some idea of what works for them.

Hope all is well with you. It's been awhile since I saw you at Chumash.

Take care,

Jim