Pictures in dictionaries: A good idea

Some words (especially nouns) are difficult to explain, but easy to draw. For such words, dictionaries should give pictures. For example, it's difficult to imagine an umbrella after reading this definition:

umbrella = an arrangement of cloth over a folded frame with a handle, used for keeping rain off the head [Longman Dictionary of English Language and Culture]

But if you look at the picture, everything becomes clear:

picture of an umbrella