During my time as a WWB user I have had the good fortune to gain numerous clients that are also WWB users. But not all users are made equal, some are, shall we say, 'design challenged', others are often 'technically challenged' and in most cases everyone just wants to get their site up and running - fast! I have also been able to help other users by digging into their project files and correct specific problems and I generally point out any glaring issues that need attention.
Quite often the common denominator is a poor understanding of imagery - not so much what is a good or bad image, although for those 'design challenged' it can be! But the biggest issues can be grouped as "Image Optimisation". I can give many examples but a couple of WWB client (no names!!!) stick out in my mind.
Client A handed over a project with a website of roughly 50 pages ~~~ The project files came in at 64Mb and when published it wouldn't fit on his hosting package!
Client B provided a small 10 page website that consumed an amazing 40Mb.
When I handed back the .wbs and project folders for Client A I had managed to reduce 64Mb to just under 2Mb and when published consumed very little space on his server. For Client B the 40Mb came in at under 1Mb.
Besides the use of Master Frame pages and Master Objects to eliminate duplication (which it self can save a great deal of disk space and your time) I managed to save a lot of space with simple image optimisation techniques and, I would like to think, improved the clients' SEO ranking at the same time.
So, after much ado, and a great deal of testing after releasing the Liquid Zoom extension (demo here) and its related example of image optimisation I decided to write an article/tutorial that I would hope will be found useful.
I doubt this is the definitive article on the subject but I am sure there is enough there to help most users.
If you spot any errors or omissions please do let me know.
Feel free to post comments here in the WWB forum and/or in my article.

EDIT: changed URL's of the demo links.