Image switching control method and image processing device

An image switching control method is executed by an image processing device and comprises the following steps: (A) detecting whether a first preset pin of a first signal input port is at a high logic level; (B) when the judgment result of the step (A) is yes, setting a first flag related to the first signal input port as a high logic level; (C) generating and outputting a first output signal according to a first input signal received by the first signal input port; (D) detecting whether the first preset pin is at a low logic level; (E) when the judgment result of the step (D) is negative, detecting whether a second preset pin of the second signal input port is a high logic level or not; (F) when the judgment result of (E) is yes, detecting whether a second flag related to the second signal input port is a high logic level or not; and (G) when the judgment result of the step (F) is yes, repeating the step (C). Therefore, the signal input ports can be automatically switched, and convenience is brought to a user