Though written entirely in Japanese, the target audience of 絵でわかる日本語 (or "Understanding Japanese through Pictures") is learners of Japanese as a foreign language. The website is made up of hundreds of short blog posts that focus on specific information, such as grammar points, common learner errors, colloquialisms, idioms, onomatopoeic language, and more. Each post features at least one cartoon, example sentences, and a good ol' fashioned explanation of the target language.
The website is probably not the most useful resource to use as a reference, as it can be very difficult to navigate. The organization is not very clear, and links to other pages, as well as ads for other websites, make it a visual maze. That aside, it is actually full of interesting information that is very useful for learners, especially if they're looking for information on language features that might not be covered in their traditional textbooks. Also, while the art is very simple, it really helps to demonstrate the concepts that each post is trying to teach. We recommend bookmarking this website and spending an hour or so just poking around and seeing what you find. You might learn something that you never expected!