.SPC File

File extension spc is associated with the Atari compressed spectrum bitmap file format used by computers developed by ATARI, like ATARI 800XL, 800XE, ATARI ST, ATARI Falcon etc.

Atari compressed spectrum bitmap file format seems to be obsolete and without support from developer.

How to open:

SPC format was originally only viewable on Atari devices.

How to convert:

It appears that you can convert these pictures to other common graphics formats using the XnView.