Often in a network, images such as JPEGs will load from top-to-bottom as data is received. This is often due to the fact that such images are typically packetized and transmitted from a beginning to an end of the image data structure, meaning that the image data making up the first part of the image is completely transmitted before the image data making up subsequent parts of the image. Consequently, while the image is being loaded the user may not have a particularly good sense of the image, since no image data from the bottom portion of the image is initially available.
To address this issue, some communication networks allow their users to automatically download images as communications including the images are received. In this way, the user can be provided with quick access to the full-quality version of the image if they do not open the message including the image right away. Problematically, in many cases a user does not ever view the downloaded image, meaning the network bandwidth used to transmit this message was wasted.