Viewing of web pages is improved by prioritizing image rendering based on positioning of images within a web page. For example, for images that are likely to be initially viewable upon presentation of the web page (i.e., prior to scrolling), compressed proxy versions are made available so that the images can be transferred and rendered more quickly. These compressed proxy images are later replaced with better quality renderings of the same images. Fetching of images that are not initially visible can be deferred until after other, more important page resources are loaded. Prioritization of page loading in this manner helps to ensure that the page becomes operational earlier, resulting in improved perceived speed and responsiveness, and greater ease of navigation.