I recommend the "WarpDT" datatypes. they can be found on Aminet or here:
http://www.warpdt.co.uk/ You can register them if you'd like to support continued development.
Plenty of other picture viewers are available, it should be mentioned, but a lot of them are pretty old and no longer supported. IMHO Multiview is just fine once properly configured.

At some point there should also be a release of "
MultiviewerNG" for classic systems, as well.