A device and method for modifying content for use on a mobile electronic device. The content includes (i) a plurality of content image files each including graphics information for generating an associated image and (ii) computer instructions including references to the plurality of image files for causing the associated images to be displayed on a display screen. A plurality of image files are selected from the content that can be combined together to form a single image file that will have a smaller file size than the sum of the file sizes of the selected image files. The selected image files are combined into a single merged image file. The computer instructions are amended to accommodate the merged image file.