When choosing a particular file format other than HTML and GIF, make sure that all the platforms have such a viewer, or otherwise some of your target audience will not be able to view the file. The size of an image file is directly proportional to the transfer time taken. The file size of a line art graphic will be much smaller than a photograph. But a color image and a grayscale one may have similar sizes. See the comparison .
Interlaced images let users see the coarse images in about half of the normal transfer time.
Users can then decide whether to stop image loading. Netscape is able to display the coarse image, other clients will only display the whole image after the downloading completed. It will load and display the low resolution image first, then load the high resolution one to replace the lower one. See this example . Alternate text Users connecting from remote sites or through modem lines may choose to 'Delay image loading'.