I believe you need WiFi, however there is a USB port on the back of the frame. I bought one for my mother and one for my mother-in-law so I don't know if either of them kept the instruction booklet or not. I will say the mother-in-law has absolutely no problems with hers, however, my mom's tends to have problems. By problems, I mean, the menu screen will just pop up and it will stay there until you clear out of it. It has no issues receiving or sending pictures.
The only way I know of is through wireless. You can obviously manually copy pictures to the memory card from a PC and then move it to the frame to transfer pictures. Without wireless, the e-mail pictures to frame functionality and such would not work.