The pair, who have previously denied that they are dating, had labelled an image of them kissing which surfaced last week as fake.
However, new colour shots appear to show the teen performers dressed in bathing suits, kissing and cuddling while together in Saint Lucia in the Caribbean.
Since the images were released, 18-year-old Gomez has been the subject of vicious Twitter attacks. One user wrote to her: "I'll kill you I swear on GOD!!! (sic)"
Another tweet read: "Wh*re cancer wh*re..like i'mm kill myself cuz i saw you and Justin kissing well thankyou Selena thankyou now i'm killing myself."
A further person messaged: "Stay away from Justin pedophile, retard wait i'm gonna kill ya in the night underneath your smelly bed."
TMZ reports that Gomez's representatives did not respond to requests for comment.
