"Freelancing" means a lot of things to a lot of different people. For illustrators, the term "freelancing" seems a bit trickier than in most other industries because almost everyone is, by definition, freelancing--going from one gig to the next, with or without the help of an agent or agency.
For me, freelancing means doing just about anything that pays fairly and falls under the umbrella of illustration, design, fine art, or creative work. In this case, I was hired by Standard Creative to paint marinara sauce portraits during a celebration of pizza's "birthday" at an event in Williamsburg last week. You can see me at 2:28.
...And here's a picture of some of the final products!