The vector stencils library "Professions" contains 58 people clipart images of different professions you can use in your presentations, illustrations and infographics.
"Electronic clip art is available in several different file formats. It is important for clip art users to understand the differences between file formats so that they can use an appropriate image file and get the resolution and detail results they need.
Clip art file formats are divided into 2 different types: bitmap or vector graphics. ...
In contrast to the grid format of bitmap images, Vector graphics file formats use geometric modeling to describe an image as a series of points, lines, curves, and polygons. Because the image is described using geometric data instead of fixed pixels, the image can be scaled to any size while retaining "resolution independence", meaning that the image can be printed at the highest resolution a printer supports, resulting in a clear, crisp image. Vector file formats are usually superior in resolution and ease of editing as compared to bitmap file formats, but are not as widely supported by software and are not well-suited for storing pixel-specific data such as scanned photographs. In the early years of electronic clip art, vector illustrations were limited to simple line art representations." [Clip art. Wikipedia]
The clip art example "Professions - Vector stencils library" was created using the ConceptDraw PRO diagramming and vector drawing software extended with the People solution from the Illustration area of ConceptDraw Solution Park.