A wireless image transmission system including i) a transmitter to transmit, by radio communication, an image signal obtained by converting an image obtained by an endoscope apparatus and ii) a receiver having a display unit on which the image signal received from the transmitter is displayed, the transmitter comprising: a communication state detection unit configured to monitor a communication state of radio communication; an editing unit configured to edit the image signal according to a mode in which the endoscope apparatus obtains an image when a change in a communication state is detected by the communication state detection unit; a transmission unit configured to transmit the image signal output from the editing unit to the receiver; a mode determination unit configured to determine a mode that is set to the endoscope apparatus from among a normal mode in which normal endoscopy is performed, a special light mode in which endoscopy with special light is performed and an ultrasonic mode in which endoscopy with ultrasonic waves is performed; and a storage unit configured to store color data reduction rate information in each of the normal mode, the special light mode, and the ultrasonic mode; and the receiver comprising: an analysis unit configured to: - edit the image signal received from the transmitter into a format enabling the image signal to be displayed on the display unit, and - detect a communication state, wherein when the image signal is to be edited, the editing unit is configured to: - obtain color data reduction rate information that corresponds to a mode determined by the mode determination unit from the storage unit, and - edit a ratio of color data according to the obtained color data reduction rate information and when the communication state detection unit detects deterioration in a communication state and the mode is the special light mode, the editing unit is configured to edit the image signal such that a ratio of a color difference Pb component becomes higher than that of a color difference Pr component. a communication state detection unit configured to monitor a communication state of radio communication; an editing unit configured to edit the image signal according to a mode in which the endoscope apparatus obtains an image when a change in a communication state is detected by the communication state detection unit; a transmission unit configured to transmit the image signal output from the editing unit to the receiver; a mode determination unit configured to determine a mode that is set to the endoscope apparatus from among a normal mode in which normal endoscopy is performed, a special light mode in which endoscopy with special light is performed and an ultrasonic mode in which endoscopy with ultrasonic waves is performed; and a storage unit configured to store color data reduction rate information in each of the normal mode, the special light mode, and the ultrasonic mode; and an analysis unit configured to: - edit the image signal received from the transmitter into a format enabling the image signal to be displayed on the display unit, and - detect a communication state, wherein - edit the image signal received from the transmitter into a format enabling the image signal to be displayed on the display unit, and - detect a communication state, wherein - obtain color data reduction rate information that corresponds to a mode determined by the mode determination unit from the storage unit, and - edit a ratio of color data according to the obtained color data reduction rate information and when the communication state detection unit detects deterioration in a communication state and the mode is the special light mode, the editing unit is configured to edit the image signal such that a ratio of a color difference Pb component becomes higher than that of a color difference Pr component.