A method, comprising: at an electronic device with a touch-sensitive surface, a display, and one or more sensors to detect intensities of contacts with the touch-sensitive surface: displaying a first user interface on the display, wherein the first user interface includes a background with a first appearance, the background of the first user interface including a representative image in a sequence of images; and one or more foreground objects (802, 804, 806, 808, 862); while displaying the first user interface on the display, detecting a first input by a first contact on the touch-sensitive surface while a first focus selector is at a location in the first user interface that corresponds to the background of the first user interface; in response to detecting the first input by the first contact, in accordance with a determination that the first contact has a characteristic intensity above a first intensity threshold, dynamically changing the appearance of the background of the first user interface without changing the appearance of the one or more foreground objects in the first user interface, wherein the dynamic change in the appearance of the background of the first user interface is based at least in part on the characteristic intensity of the first contact, and wherein dynamically changing the appearance of the background of the first user interface includes displaying in sequence at least some of the sequence of images based at least in part on the characteristic intensity of the first contact; and; while detecting the first input by the first contact, after determining that the first contact has a characteristic intensity above the first intensity threshold: detecting a decrease in the characteristic intensity of the first contact; and, in response to detecting the decrease in the characteristic intensity of the first contact, reversing the changing of the appearance of the background of the first user interface. displaying a first user interface on the display, wherein the first user interface includes a background with a first appearance, the background of the first user interface including a representative image in a sequence of images; and one or more foreground objects (802, 804, 806, 808, 862); a background with a first appearance, the background of the first user interface including a representative image in a sequence of images; and one or more foreground objects (802, 804, 806, 808, 862); while displaying the first user interface on the display, detecting a first input by a first contact on the touch-sensitive surface while a first focus selector is at a location in the first user interface that corresponds to the background of the first user interface; in response to detecting the first input by the first contact, in accordance with a determination that the first contact has a characteristic intensity above a first intensity threshold, dynamically changing the appearance of the background of the first user interface without changing the appearance of the one or more foreground objects in the first user interface, wherein the dynamic change in the appearance of the background of the first user interface is based at least in part on the characteristic intensity of the first contact, and wherein dynamically changing the appearance of the background of the first user interface includes displaying in sequence at least some of the sequence of images based at least in part on the characteristic intensity of the first contact; and; while detecting the first input by the first contact, after determining that the first contact has a characteristic intensity above the first intensity threshold: detecting a decrease in the characteristic intensity of the first contact; and, in response to detecting the decrease in the characteristic intensity of the first contact, reversing the changing of the appearance of the background of the first user interface.