What are these images with strange text on them?

These are CAPTCHA images. They're designed to prevent malicious programs and spambots from submitting unwanted and offensive content to webforms.

Real people should find it relatively easy to read the characters and type them in the verification field, while it is very difficult for automated programs to do this. This verfies that you are indeed a 'real person' and helps ensure that what you send doesn't get overlooked among a lot of 'junk' entries from spambots.