I have several photographs of Elvis, Elvis & Glen Campbell & Elvis & Priscilla. How can I find out how much these pictures are worth and how much someone would pay me for them?

they are true photos! my uncle lived in Memphis, and was able to get these pictures as they were leaving from somewhere; Can u give me some idea what someone might be willing to pay? of you?

I've been away, so I'm sorry I didn't reply sooner. Are the photographs are meer along the lines of a portrait, where u would easily be able to tell it was Elvis, of are they meer like group pictures? I know of someone who is interested.