Images can make all the difference in a presentation. Many theories and approaches exist for their proper use, but these aren't necessarily suitable for every presentation. One distinction lies between schematic and concrete representations, as will be shown below.

Schematic or conceptual representation
Instead of showing a picture of the subject being discussed, a schematic representation of the subject or the underlying concept is used. For example, in a presentation about apple production, a schematic representation would be a sketch of the production process: drawn trees and apples, stick figures picking fruit, and drawn trucks transporting filled baskets – this is what a schematic representation might look like.

In contrast, a concrete representation would be, for example, a photograph of the production facility or the apples on the tree. Depending on the situation in the presentation, which type of illustration makes more sense. A schematic representation is generally always useful when dealing with abstract processes. The actual apple can be represented by a photograph, while the production process, in its abstract form, requires a conceptual representation.

Concrete or explicit form of representation
As already mentioned, a concrete representation of something is only meaningful when it truly reflects that thing in its primary characteristic. Images, therefore, that mean exactly what they depict. In a presentation showing different ways to draw arrows, the arrows represent precisely what they are: different representations of arrows. However, if these same arrows appear, for example, in the context of a flowchart, then they represent a process.

If a color code is then assigned to them (e.g., yellow for external, blue for internal processes), the level of meaning becomes even more abstract.

Generally speaking, schematic diagrams are preferable in presentations. In fact, they facilitate the communication of complex content, especially for visual learners. Concrete diagrams, when used correctly, can also be useful, but there must be a situation where it is appropriate to show what is being described in this explicit form.