So ComputerCraft 1.76 (the first build for MineCraft 1.8) offers an expanded fontset, including characters that happen to be fairly convenient for drawing pixel art with. oli's function here provides a great illustration as to how they can be used to plot most any 2x3 pattern of pixels within any given character space.
This here is an API to help automate the process; pass in a paintutils image, and it passes out a little version that can be blitted, reduced using the "smaller pixels" available within the new font. It also offers functions to save/load/draw these images.
You can alternatively generate a "window" that can be treated as a regular term object, which'll automatically shrink anything you "draw" into it.
There's a bit of a catch in that there's the potential for some loss of colour information during the conversion process. It fudges things as best it can, but the less complex your image is, the better the results should be (pure black and white should always be perfect, for example). You'll also have better results if the original image dimensions have a width divisible by two and a height divisible by 3.
For quick reference, a regular ComputerCraft terminal display can effectively display images of up to 102x57 pixels using the new fontset (up from 51x19), whereas external monitors (when built up to full size and with a text scale set to 0.5) can go up to 328x243 (from 164x81).
Furthermore, here's a simple example script which imports images using my GIF API, and then draws them on an attached monitor:
And here are some screenshots of what a few loaded images might look like:
Edited by Bomb Bloke, 15 May 2016 - 11:44 AM.