gEDA-user: [pcb] embedding raster image size in png exports

[DJ Delorie]

> Also, out of curiosity, what does "xy-max" that appears in the png
> export dialog in PCB do?

It limits the size of the image to NxN pixels, but maintains the
aspect ratio.  For example, if you set it to 400, a 6000x8000 mil
board would yeild a 300x400 image, but a 6000x4500 board yeilds a
400x300 image.

This is good for bulk-converting to web page thumbnails.