RECOIL (Retro Computer Image Library) is a viewer of pictures in native formats of 20th century computers: Amiga, Amstrad CPC, Apple II, Atari 8-bit, Atari Portfolio, Atari ST/TT/Falcon, BBC Micro, Commodore VIC-20, Commodore 16, Commodore 64, Commodore 128, Electronika BK, FM Towns, Macintosh 128K, MSX, NEC PC-80/88/98, Oric, Psion Series 3, SAM Coupé, Sharp X68000, Tandy 1000, Timex 2048, TRS-80, TRS-80 Color Computer, ZX81 and ZX Spectrum.
RECOIL opens over 500 different file formats. See https://recoil.sourceforge.net/ for the full list of supported formats and some example files.