Once you've hit send, the contents of your message will appear to the recipient as a series of orange censorship bars, and can only be revealed by tracing a finger across them. Once it's been read, the message disappears. Similarly, a photo you send through Confide is blurred out, and then promptly disappears once it's revealed. To protect against any funny business, every message is encrypted end to end, and if a recipient attempts to take a screenshot, it'll alert you and kick them out of the message (although, since the censorship bar ensures only a portion of the message is revealed at any one time, getting a damning screenshot in the first place would be tough).
As useful as it can be to cover your tracks, there is one significant catch: Confide only works when both the sender and recipient have it downloaded. So, just make sure your secret lover/whistleblower pals/Edward Snowden has it on their phone, too.