This blog post covers the publication of multimedia on GBIF. However, it is not intended to be a documentation. For more information, please check the references below.
Interesting post. Probably will be very useful for data publishers.
Super relevant and useful. Although not intended to be documentation, it’s the best documentation on the subject I’ve seen 
Thanks for this useful summary!
If there is one thing I would still wish for, it is a very simple, direct example of a concrete case, to show what that could look like when configuring data for publishing through GBIF.org, and what it shows up at (facet filter search, image gallery). That could be just a screenshot of the multimedia section on a page like https://www.gbif.org/occurrence/1265883603, maybe listing the other supported values under the “Type” again, and a few more examples of what else could go under Format in the concrete case. Maybe it could also show where those values come from in the mapping of e.g. a simple multimedia extension (another screenshot?). Nothing all-encompassing and extensive, just the illustration of one concrete case.
Thanks for the comment!
I updated the post with the illustrated example you suggested.
I want to suggest Internet Archive as a good solution for images storage when biological collections/publishers don’t have their own server. Here is a good example from a Colombian strain collection. The images have the occurrenceID to link it to the record on GBIF (see Serratia marcescens : Free Download, Borrow, and Streaming : Internet Archive) and vice versa (see Occurrence Detail 2270823025).