A picture data transmission method and device are disclosed in the present invention. The picture data transmission method comprises: recoding a first picture to be transmitted, by a picture data sending terminal, to obtain a second picture, wherein the file size of the second picture is smaller than that of the first picture, and a quality difference between the second picture and the first picture is less than a pre-set threshold; and selecting one of the first picture and the second picture according to quality values of the first picture and the second picture and sending the selected picture to a picture data receiving terminal. According to the present invention, pictures can be recoded to obtain pictures with a small amount of data for data transmission, without affecting the picture quality, thereby saving network resources and reducing storage pressure.