Here's what I explained: This work is a portrait of Giovanni di Nicolao Arnolfini and his wife, but is not intended as a record of their wedding. His wife is not pregnant, as is often thought, but holding up her full-skirted dress in the contemporary fashion. Arnolfini was a member of a merchant family from Lucca living in Bruges. The couple are shown in a well-appointed interior.
The ornate Latin signature translates as 'Jan van Eyck was here 1434'. The similarity to modern graffiti is not accidental. Van Eyck often inscribed his pictures in a witty way. The mirror reflects two figures in the doorway. One may be the painter himself. Arnolfini raises his right hand as he faces them, perhaps as a greeting.
Van Eyck was intensely interested in the effects of light: oil paint allowed him to depict it with great subtlety in this picture, notably on the gleaming brass chandelier.