File extension pgf is used by following file type(s):

File extension pgf file type description:
Portfolio Graphics image format

Portfolio Graphics image format.

The Portfolio's screen is 240 x 64 pixels when in graphics mode. Being monochome, it only takes 1 bit to represent a single pixel. Therefore, 8 pixels per byte. A PGF ends up being 64 rows of 30 bytes each for a total of 1920 bytes. PGF files could simply be copied from video ram to disk and vice-versa.

Related programs
that open pgf files:
XnView