How Does Word Verification Work?
Automated programs can't "read" the word you see in the box: only humans can. When you enter this word, it ensures that this order is coming from a real person and not an automated program.
If you don't see an image, make sure your browser is set to display images and try again. If you're not sure what the word is, make your best guess. If you're incorrect, you'll get another chance to enter a different word on the next screen.