Something gilded looks like gold, whether it is or not. If you've heard the expression "all that glitters is not gold," it's especially true of anything gilded.
You might have first heard the word gilded in the name of a historical period in the U.S. known as The Gilded Age; the name suggests that the appearance of wealth concealed actual poverty. Gilded is often used to point out illusion in this way, but if no illusion is intended, it need not be a negative word. I think the gilded doves in your painting are especially lovely.