This page aims to contain a comprehensive list of metrics and graphs for Media Viewer, both from a usage and technical perspective.
These servers are responsible for generating thumbnails, which Media Viewer triggers a lot since thumbnails are generated on-the-fly when they don't exist yet.
Media Viewer relies on several APIs on the PHP side, some of which are specific to Media Viewer.
Thumbnails, after being generated, are streamed using the StreamFile method.
Presumably where images are stored. Not sure if originals or thumbs, we should clarify that with ops.