In addition to pictures, short videos can be sent.
The captions in the videos and pictures can only be as long as the screen is wide. If you would like to fit more text on the screen, either tilt your device sideways so your text bar is longer, or write the words using the draw tool on snapchat. The color of the pen can be changed.
While not every snapchat user sexts, snapchat is a wonderful tool for sexting because after the image is opened the image deletes after a set amount of time between 1 and 10 seconds.
If the viewer of the image is quick enough, he/she may take a screenshot of the image. However if a screenshot is taken you will be notified by snapchat.
Snapchat is a real pain in the ass if you don't have a front-facing camera on your device.
Girl: no, I don't have a phone. The plans are so expensive! I have an iTouch though so I can Snapchat you.
Guy: yeah, I have a one too. What's your snapchat?
Girl: *gives out snapchat name*
Guy: cool! I'll hit you up later tonight (;