Amiga

The Amiga includes a lovely facility known as datatypes, basically an extension of normal shared libraries (or DLLs) to provide generic data handling capabilities. With this facility, any datatypes-aware program--whether viewer, web browser, or image editor--can be extended after the fact, simply by adding the appropriate datatype for whatever new format comes along. In the case of PNG, two datatypes are available: Cloanto's and Andreas Kleinert's:

http://www.aminet.org/pub/aminet/util/dtype/PNG_dt.lha
http://www.aminet.org/pub/aminet/util/dtype/akPNG-dt.lha

Except where noted, all of the Amiga image viewers that follow require one of these datatypes for PNG support. (Indeed, there are probably many other datatypes-based viewers that are not listed here.)

Image Engineer

Version 3.41, Simon Edwards. Conversion capabilities. Image Engineer uses the SuperView Library (see Cross-Platform Libraries) for its image support instead of datatypes.

http://amigaworld.com/support/imageengineer/

Multiview

Amiga. Multiview was apparently a standard, datatypes-aware viewer shipped as part of the Amiga operating system.

PPShow

Version 4.0, Nico François. Insofar as its last release was in February 1994--more than a year before the PNG specification was frozen--PPShow is a fine example of the power of Amiga datatypes.

http://www.aminet.org/pub/aminet/gfx/show/PPShow40.lha

SViewII

Version 8.10, Andreas Kleinert. Conversion capabilities. Formerly known as SuperView, SViewII includes the SuperView Library (discussed in Cross-Platform Libraries) for all image I/O, instead of datatypes, despite the fact that Andreas wrote one of the available datatypes.

http://home.t-online.de/home/Andreas_Kleinert/sview.htm

ViewDT

Cloanto. ViewDT is a demo viewer included with Cloanto's PNG datatype; source code is included. Cloanto also once had a viewer called Personal View, but it no longer seems to exist.

http://www.aminet.org/pub/aminet/util/dtype/PNG_dt.lha

ViewTEK

Version 2.1, Thomas Krehbiel.

http://www.aminet.org/pub/aminet/gfx/show/ViewTEK21.lha

Visage

Version 39.21, Magnus Holmgren. Visage has had native PNG support since version 39.12.

http://www.algonet.se/~lear/visage.html