decorative plate; plate with a picture
A plate that is decorated with a picture or pattern, often used for display rather than everyday eating.
At my grandmother's house, a beautiful decorative plate is displayed.
Rare or specialized use; in art contexts, may refer to a palette (for mixing paints), but the more common word is パレット.
I found a palette labeled '絵皿' in an old art supply store.
Compound of 絵 (picture) and 皿 (plate). The palette sense likely arose from the resemblance of a painter's palette to a plate with dabs of color.