Before you purchase or use royalty-free clipart you should know the two main types of formats. Clipart can come in a vector format and a raster format.
Publishing programs such as Microsoft Publisher. Many publishing programs contain a data base of artwork that can be used in any document
Ideally, you should look for clipart that comes in a set of images designed by the same artist specifically for restaurant promotion. The mistake most independent restaurant owners make is that they pick up a piece of art here and a piece of art there, and pretty soon they have the house that Jack built. The illustrated hamburger is more graphic and contemporary; the illustration of the Chef may be more cartoony; a background illustration of a country setting may be more realistic; graphic symbols of the various offerings may have a high-tech look that clashes with the warm atmosphere you're trying to create.