1. An image encoding method of encoding image data, and outputting encoded image data, comprising: a step of generating difference data between a predicted image for an image to be encoded and the image to be encoded; a step of encoding the difference data and generating the encoded image data, and outputting the generated encoded image data; a step of decoding the encoded image data, and generating a local decoded image; a step of generating the predicted image by using the local decoded image; and a step of outputting, using a predicted image generating part of an image decoding apparatus, one of an in-screen or between-screen predicted image, and an interpolation predicted image generated by executing move searching between the local decoded images as the predicted image based on a skip mode that includes information associated with the image to be encoded, the skip mode being a process in which previous information of a frame is copied and in which data of a pixel block is not compressed, wherein the step of outputting comprises: when the skip mode is valid, outputting the interpolation predicted image as the predicted image, such that the interpolation predicted image is used for compression of every pixel block to be encoded; and when the skip mode is invalid, outputting the in-screen or between-screen predicted image as the predicted image, such that the in-screen and between-screen predicted image are encoded by being switched for every pixel.