An image system includes: a display device configured to display an image; and an eyeglasses device for viewing the image displayed by the display device, wherein the display device includes: a display portion configured to display in time series the image to be viewed through the eyeglasses device; a signal generation portion configured to generate a synchronization signal for synchronizing timing of switching of frames of the image; and a transmission portion configured to transmit the synchronization signal, the eyeglasses device includes: an optical filter portion configured to adjust an amount of light of the image; a reception portion configured to receive the synchronization signal transmitted from the transmission portion; and a control portion configured to control action of the optical filter portion corresponding to the switching of the frames of the image, based on the synchronization signal, the signal generation portion further generates a parameter signal including action information for defining an action of the optical filter portion, the transmission portion transmits the parameter signal to the reception portion, and the control portion controls the action of the optical filter portion according to the action information of the parameter signal for defining the action of the optical filter portion.