Dipinto vs. quadro
The Italian words 'dipinto' and 'quadro' both refer to paintings, but they have subtle differences in usage and connotation.
Dipinto
'Dipinto' is both a noun and the past participle of the verb 'dipingere' (to paint). As a noun, it refers to any painted work, regardless of its shape or frame.
Il dipinto di Leonardo da Vinci è famoso in tutto il mondo.
(Leonardo da Vinci's painting is famous worldwide.)
Ho visto un bellissimo dipinto murale nella piazza principale.
(I saw a beautiful mural painting in the main square.)
Quadro
'Quadro' specifically refers to a framed painting, usually rectangular or square in shape. It implies a more traditional, contained artwork.
Ho appeso un nuovo quadro nel mio salotto.
(I hung a new painting in my living room.)
La galleria d'arte espone molti quadri di artisti contemporanei.
(The art gallery exhibits many paintings by contemporary artists.)
Summary
While 'dipinto' is a broader term that can refer to any painted work, including murals or frescoes, 'quadro' specifically denotes a framed, typically rectangular painting. 'Dipinto' emphasizes the act of painting, while 'quadro' focuses on the finished, framed product.