Art and culture cannot be separated. Art reflects culture, and a culture is partly defined by its art.
Here is a definition I made for myself (not from the dictionary) when I was taking an introductory art class:
"Art is the visual expression of the ideas, experiences, customs, products, or values of a society, an era or an individual. It transcends the limitations of culture, language, distance and time."
Of course, art can be literature, music and dance as well as visual representation, but you can see how culture and art are intertwined.
So Spanish art though the centuries reflects the ideas of the Spaniards (who themselves included mixtures of ancient tribes, Romans, and North Africans, who were Christians, Jews or Muslims). Imagine how these different factors impacted how Spanish culture developed. Spanish culture can be identified and appreciated through the art produced by all these differing factors.