Describe when references to graphics, figures, and tables are required

[Miciah]

The guide cautions against excessive and non-descriptive cross-references and over-reliance on cross-references, but it does not say when cross-references are expected.

I am wondering (a) whether it is all right to have dangling (unreferenced) graphics, figures, or tables; (b) whether every figure etc. should be implicitly or explicitly mentioned at least once in the text; or (c) whether every figure etc. should be referenced explicitly by its label at least once.

Generally, I would expect (b) or (c), which is what I was taught in college, and some manuals say the same:

• "With a few exceptions—such as cover illustrations used to grab attention—graphics should be accompanied by clear references within your text" (Technical Communication: A Practical Approach Pfeiffer, W.S., 2006).
• The APA Publication Manual states, "An informative table supplements—rather than duplicates—the text. In the text, refer to every table and tell the reader what to look for", and the manual further has a "Figure Checklist" with an item, "Are all figures mentioned in the text?".
• Purdue OWL's MLA guide states, "The illustration label and number should always appear in two places: the document main text (e.g. see fig. 1) and near the illustration itself (Fig. 1)."

I found seemingly contradictory guidelines in the IBM Style Guide, which at one point seems to be saying (b): "Always introduce a figure with a sentence immediately preceding it, and use a period or a colon to end the sentence. If you present the same type of information in two or more consecutive figures, you do not have to introduce each specific figure, but you must introduce the group of figures", but later states, "It is not necessary to use a cross reference to a figure or table in text if the figure or table is not referred to, or if it is referred to in such a way that the figure or table can be identified without a number", which looks like (a).

Could the Style Guide clarify this point?