Do I have to cite illustrations?

The same applies to illustrations – diagrams, charts, tables, photos, etc. – as to any other material that you use in your academic work … as soon as it is not your own work, you must reference it! It does not matter whether you create the illustration yourself based on a template or scan and insert it as an image into your text.

Here are a few potential situations and how to proceed in these:

• Case 1: You directly copy or scan an illustration. As with all other citations, cite the source according to the guidelines of your citation style, for example, “Source: Maier 2010, p. 35”. This information can either be placed directly below the image or integrated into the caption as either a footnote or in brackets, as the citation style requires.
• Case 2: You change the content and/or design of an author’s illustration, e.g. by omitting a bar in a diagram that is not relevant to you or by displaying a sequence vertically instead of horizontally. Include a sentence in your reference that says something along the lines of “Adapted from: Maier 2010, p. 35, omitting X/expanding Y”. Be as specific as possible about the changes that you have made.
• Case 3: You design your own illustration based on external (raw) data: as in Case 1, you are required to provide the source of the data.
• Case 4: You illustrate a fact without referring to external illustrations or data: You do not have to state the source. Nevertheless, your own contribution can be explicitly mentioned with “Source: own illustration”.

As a general rule, only use illustrations that relate to the content of your paper, illustrate something important and are explicitly discussed in the text. In this way, you ensure that the illustration functions as necessary proof of your explanations. This entitles you to use and cite them without needing to obtain permission from the author.

For images that you want to use solely as decoration and not to expand on your paper academically, different copyright rules apply. You can read more about this in the book mentioned below on pg. 195.