It's totally up to you. If you have a specific picture you would like signed then send that. If they sign it then that's a bonus. If you are just requesting a signed picture and don't include one then it's best to include an index card just in case, as there may be some celebrities who don't send their own pictures.
But yes, most celebrities have their own pictures which they send out so they may not have time to sign everyones individual pictures. But like I said before, if you can't supply a picture then it's a good idea to pop an index card in just in case :)

Hi eorakai :D ,

First, welcome to fanmail.biz {clap}

In my opinion sending pictures doesn't increase or decrease your chances of receiving an autograph.
Most celebrities send their own pictures, very few don't (compared to those that do.)

I always check previous feedback to see if the celebrity I am sending to sends their own pictures.

-corekid [reindeer]

Some celebs will send photos to you, but it's always best to send something to them! {thumb2}

RYAN J.

ok so if u want a signed autograph from someone do you give them the picture of them that u want signed or do they supply one :)