'Ireland Dublin Castle House Island' - is a work of Photoshop
In many places on the internet has seen this picture, saying it is the "Castle Island House" in Dublin Ireland, but it is actually a Photoshop job.
The island is "James Bond Island" in Khao Phing Kan, Thailand.
And construction is the Lichtenstein castle in Baden-Württemberg, Germany.
Source: Castle House Island in Dublin, Ireland