This program is part of Netpbm. pbmto4425 displays PBM format images on an AT&T 4425 ASCII terminal using that terminal's mosaic graphics character set. The program should also work with other VT100-like terminals with mosaic graphics character sets such as the C. Itoh CIT-101, but it has not yet been tested on terminals other than the 4425.
Pbmto4425 puts the terminal into 132 column mode to achieve the maximum resolution of the terminal. In this mode the terminal has a resolution of 264 columns by 69 rows. The pixels have an aspect ratio of 1:2.6, therefore an image should be processed before being displayed in a manner such as this:
% pamscale -xscale 2.6 pamfile \
| pamscale -xysize 264 69 \
| ppmtopgm \
| pamditherbw \
| pbmto4425