Weboword is a visual vocabulary site that aims to help you to build your vocabulary through hand-drawn, situation specific cartoons, drawings and sketches. Here's an example:
Other resources on the site include a weekly crossword puzzle and Weboword Connect, an online community for vocabulary lovers.
If you like the Weboword approach, you might like to subscribe to Weboword Express, a monthly PDF pack which combines Weboword’s daily visual vocabulary and weekly crossword with premium content to aid vocabulary development and English language learning. You can view a sample here.

