How can I make a custom sprite larger than 16 X 16 pixels?

I made some custom spites for a video game that I'm really exited about making, But some of the sprites are larger than 16 by 16 pixels. I didn't think this would be a problem until I looked at the sprite definitions and saw that my player sprite,(which is a man) was broken in two, his top half and his bottom half. In the already made sprite sheets there are sprites clearly bigger than 16 X 16 pixels,(the smilebasic logo sprite for example) so how can I do it with custom sprites? Is it even possible? Thanks in advance.