Note: How the Sections are constructed also affects load on some devices.
Older 'Paged' display typically loaded the current Section.
Smooth Scroll devices have to load the entire book (I think the Calibre Viewer falls here)
Many images in a single file, all have to load (render) with that Section.
Wrap the <img tag in messy (nested) code and it gets slower.
Lean and Mean code is
