Hi Peter,
I use Visage which has plenty of tooltypes for setting such as SLIDESHOW SCALE etc
See
http://aminet.net/package/gfx/show/Visage
"Visage is an IFF ILBM/JPeg/PNG/Datatypes viewer for the AmigaOS version 3.0 and higher. Main features include:
Supports AA (AGA), ECS, RTG, PCHG, SHAM and CLUT.
Can display "deep" pictures in all formats on ECS Amigas, rendered in HAM, "normal" color or grayscale.
Can scale "rendered" pictures to fit the screen.
Extensive monitor support. Uses a BestModeID()-like function to find a suitable mode (if needed)."
Regards, Michael
aka rockape