Hi Andy,
I use Visage see Aminet
http://aminet.net/gfx/show/Visage.readmeIf you muli-select pictures to view, it pre-loads the next picture into memory so, as you view the first the next pic is ready almost instantaneously.
Also, Visage is very configuarable using its Icon Tooltypes, for example you can set to SCALE so the picture fits your monitor screen.
Regards, Michael
aka rockape