If the resolution of the images in your source documents is set for print, such as a resolution of 300 dots per inch (dpi) or higher, you may want to reduce the image resolution for online delivery. High dpi images create larger files that require more time to download. In addition, most monitors display a resolution of 96 dpi, so higher resolutions do not increase the quality of the image displayed online.

Although transforming an image from 300 dpi to 96 dpi helps optimize your images for online delivery, the width and height of your images is also affected. Because a resolution of 300 dpi contains more dots per inch than a resolution of 96 dpi, when ePublisher transforms the image, the image will be roughly 68% smaller than the original image. For example, a 300 dpi image that is 100 x 100 pixels will be 32 x 32 pixels when transformed to a 96 dpi image.

To counter this effect, use the Scale % option in conjunction with the Render DPI option to control the size of your images. In the example of transforming a 300 dpi image to 96 dpi, set the Scale % option to 312, which then generates an image that has roughly the same dimensions as the original source image. You can also use the Scale % and Render DPI options together with the Maximum image height and Maximum image width options to make sure your images are correctly sized for online delivery.