I'm thinking about layout on pages where the main asset is visual — for instance, a photo of an item from the collection on a museum website, or embedded video as on YouTube and many news sites. Sometimes a title or other brief, relevant info is given above the video (as on YouTube), and sometimes text that sets the context for the image is shown immediately below (as in picture captions on news sites). Ideally, you want people to read the text that introduces and/or summarises the photo or video; this is likely to be at most one or two lines of text. It might be a title or just an explanation of the object and its context.
The F-pattern for reading suggests (unsurprisingly) that English speakers start reading at the top of the page and then work their way down in horizontal stripes, so putting a title above the image makes sense from a "setting the context" point of view — it's probably not very contentious to say that content near the top of a page gets more eyeballs than the stuff further down. However, the brain is considerably faster at processing images than it is at processing text, which might mean that we finish process the image content before we're done processing the words, even if the words are shown first on the page. There's also a whole thing about page layout, whereby images and white space guide the eye — for instance, cogapp.com seems to do a really nice job guiding the eye down the page to the statement about what they do. So I don't know how easy it is to talk about this in the abstract, as to some extent it's also going to be dependent on visual design.
Anyway, my question: is there any hard evidence as to whether it's preferable to put related text above or below the image, from the point of view of getting people to read and process the words? (I'm not sure whether merely fixating on the words would count; I want to know they've actually processed the written content in a meaningful way :)