Overview
Inline diagrams and schema markup are both structured signals to crawlers, but they target different surfaces. Inline diagrams give crawlers parseable visual content. Schema markup gives crawlers structured metadata about anything on the page — articles, products, FAQs, diagrams, breadcrumbs, the lot.
The conceptual difference
Schema markup is the broader category. Article schema describes the article. FAQPage schema describes the Q&A section. Product schema describes a product. ImageObject schema (a subset of schema markup) describes images including inline diagrams.
Inline diagrams are one specific kind of content. They're not a schema type; they're a content type that BENEFITS from being paired with ImageObject schema.
So comparing them is slightly category-confused. The right framing: inline diagrams are content; schema markup is metadata. Both should be on every substantive page, and together they're what makes a page citation-eligible by AI surfaces.
Where the overlap matters
When you add an inline diagram, you should also add ImageObject schema for it (a single JSON-LD block in the head). When you add an article, you should add Article schema. When you add a FAQ section, you should add FAQPage schema. The pattern is consistent: substantive content gets a paired structured-data declaration.
A page with rich content but no schema is significantly less citable than one with both. A page with extensive schema but thin content is recognized as thin and downranked. Both are required; neither substitutes for the other.