As for the scenes he painted, they often were quirky. In some cases there was a hint of humor, but humor from an odd, sometimes hard to understand viewpoint.
His English Wikipedia entry is here. From there you might link to a longer Italian entry.
The harlequin in the previous image reappears here.
Example of a landscape painting where Donghi uses a different style.
The title refers to her blue outfit, yet it's hard to avoid noticing the gloved hand.
Just by looking at this painting it's hard to say whether Donghi made a typical work honoring Mussolini or whether this was a subtle satire of such works. I suspect the latter.
"Children at the Window" -- a postwar work.
This and the next two paintings as seen via my iPhone in Venice's Ca' Pesaro museum.
"The Parting" is the short title for this couple at a train station.