MK, Epcot, DS and AK all have photographers as you walk into the parks. You get a photo with a background and sometimes characters are added digitally. If you want a photo with Mickey, try Studio M at DTD (a real live Mickey, not digitally added). You can also get a photo made at the Exposition Hall in the MK to the right as you enter the park. In Epcot, you can get a photo made at Imageworks near JIM with Figment. There are even photographers who will take your photo as you float around the lazy creek in BB and TL or if you do family raft rides.
But, if you have a character meal, the characters come to your table and you can take your own photo with the characters.