Images account for a significant and growing fraction of Web downloads. The traditional approach to transporting images uses TCP, which provides a generic reliable, in-order eam abstraction, but which is overly restrictive for image data. We analyze the progression of image quality at the receiver with time and show that the in-order delivery ion provided by a TCP-based approach prevents the receiver application from processing and rendering portions of an image when they actually arrive. The end result is that an image is rendered in bursts interspersed with long idle times rather than smoothly. This paper describes the design, implementation, and evaluation of the Image Transport Protocol (ITP) for image transmission over loss-prone congested or wireless networks. ITP improves user-perceived latency using applicationlevel framing (ALF) and out-of-order Application Data Unit (ADU) delivery, achieving significantly better interactive performance as measured by the evolution of peak ...