Skins and Art

All of a world's living things are film strips: one bitmap, with the frames side by side, that the game cuts into cells and animates. Hero skins live in the game's skins/ folder and are shared by every world; monsters live in the world's own monsters/ folder.

The bitmap

An 8-bit (256-colour) BMP using the game palette, souls.pal in the game's art/ folder. Run-length compression is fine and makes the file much smaller.
The top-left pixel is the transparent colour. ReBreather masks it on every sprite it draws, so the teal box some old viewers showed never appears.
Cells are as tall as the strip and all the same width. Keep the figure inside its cell.
Use your own work. A skin is seen by everyone in the scene, so keep it free of other people's characters and of anything you would not show a child.

Hero skins

A hero strip holds, in order: nine walking cells for the map (three directions, three frames each), then ready, attack, pain, chat and credits, and optionally a magic cell after those. Draw the figure facing left. /skin opens the picker to try one on, and the DEFAULT_SKIN row of a class says which skin a new hero of that class wears.

Monster strips

A monster strip holds a credits cell (unused in play), then ready, attacking, pain and growling, and optionally a blank cell and a magic cell. Monsters face down and to the right, toward the heroes. The monster's table row sets its scale, a colour table for a recoloured variant and whether it is drawn transparent, so one strip can serve a whole family.

Looking at strips

/villagers opens the film-strip viewer on the world's monsters/ folder and /art on the art/ folder. /pal 3 forces every recoloured skin through colour table 3, which is the quick way to see what the tables do.

Maps and scenes

Map pictures (usually JPEG) go in maps/. Anything much over a thousand pixels wide is shrunk before drawing and the shrunken copy is cached, so a large picture costs the player disk space rather than speed. Scene backgrounds go in scenes/; /bkgnd name tries one on the current scene. The script's BKGND can also scale a background and shift it down.

Item and spell sheets

Icons for items, spells and trophies come from sheets in art/, one per item class, each a row of square cells (3:4 for armor, weapons and shields). A world's art/ folder overrides the game's sheet of the same name, so to give your world its own swords, ship a swords sheet. A spell's casting effect is a row on the effects sheet, chosen in the spells table.