Don't know where this has been hiding, but this has never popped up in any of my searches before now:

http://www.rls.org.uk/

Resources for Learning in Scotland (RLS) is a resource base headed by the National Library of Scotland (NLS) and SCRAN - involving over 100 Scottish archives and libraries. There are over 107 thousand records, 650 resource packs and 26 websites on Scotland's social, cultural and industrial heritage.

Unless I'm mistaken (and that would be nothing new of course ) although the pics it provides are just small versions of SCRAN's carefully guarded originals, they seem to be a bit larger and of better resolution the tiny effort that appears on SCRAN's own site.

There's almost 400 pics from one of my own favourites, the scientific collection at the Hunterian Museum, and it includes a number of examples of the original Transatlantic telegraph cables (that the ones they dropped down there way before TAT-1).