Almost everyday I read METRO (a free paper) in PDF format. I have found its comic strips so funny I started using them in order to introduce the topic of the lessons in some of my classes.
I'd like to show you some examples.
I used this one for a pre-intermediate level. The purpose of the class was:
VOCABULARY: food (fruit & vegetables)
GRAMMAR: countable & uncountable nouns
I used this comic strip for an intermediate level. Students were studying how to write a cv, how to behave during their job interview and how to keep their job.
Initially I showed them just the first picture, asking them what the girl was doing and then whether it had ever happened to them to oversleep and get to work late. Then we had a look at the lines. Also in this case there are two key words: EMPLOYER and EMPLOYEE.
I think you can use comic strips with all levels and as the IMAGE CONFERENCE suggested, we need to stimulate our imagination by means of pictures.