There are images, raster graphics, and vector graphics. These are covered by two open-source communities that create tools to create these. While there are many more open-source applications for these types of graphics, the two mentioned below are the most popular.
They also run natively on the most operating systems.
Pages associated with each link give introductions to the applications:
Like a word processor, a desktop publishing application is designed to deliver a document that is a combination of text and art.
The more advanced ones, can handle a more full print-color spectrum. Scribus, the most popular open-source DTP on the market can handle professional print jobs. It is comparable to Adobe InDesign and QuarkXpress.
It runs natively on the most operating systems.