The eyelid graphics format is explained on the “Preparing Graphics” page. These are 1-bit BMPs, 240 pixels square. Use the upperEyelid and lowerEyelid settings to specify the filenames of these images.

Eyelids are one of those global (not configurable per-eye) things. The design of the eyelid graphics might be symmetrical or asymmetrical…some eye designs might provide two sets of eyelid images, one for a single-eye device (like HalloWing M4) and another for the Monster M4SK, where the left and right eyelid shapes are mirrored.

If you want no eyelids at all, just leave out any upperEyelid or lowerEyelid filenames. You’ll then have a circular unblinking eye…looks good for skulls!

With eyelids enabled, normally the upper lid “tracks” the movement of the pupil (when the eye looks down, the eyelid follows with it). This is something that eyes do in real life…but some folks think it looks sleepy, or just want a particular caffeinated look. Use the tracking keyword with a value of false to disable the eyelid tracking and maintain wide-open eyes.