A glyph image is a clean picture of one character - a sample cleaned up, or a missing character drawn,
by hand or with an AI image tool - used in place of the scans when you Regenerate (both fonts; the scans of that character are kept, just not used).
Type which character each one is. It's placed for you: onto the character's own average when it has samples, otherwise where a
standard font puts it, scaled to this face's capitals. Drag to move it, wheel to scale (Shift = fine), arrows nudge.
Name a file after its character (&.png, uni0026.png) and it's filled in. To clean up a glyph you already have,
open it in Results and save its picture.