As a user, I want to load images faster, even if it means I see lower resolution versions.
Many of the images shown in Media Viewer are quite large (e.g.: over 2Mb), which takes a long time to load from scratch (if nobody has pre-loaded it already).
Instead of loading these high resolution files in the lightbox, try loading the next size down, to match their browser window size, rather than their screen size. Even that smaller size is only 20% less than the current size, it is likely to take less time to load, and every second counts.
Treat the full-screen mode as a separate case from the lightbox mode, so we can load a smaller image for the lightbox mode. Since the full-screen button is not used often (e.g. 9% of thumbnail clicks), we can afford to reload a larger version of the file when the user clicks on the full-screen button.
It may also be possible to serve even smaller files if we find that the user has a really slow connection: we can detect the user’s connection speed by measuring how long it takes them to load a file.
<u>Note</u>: Images continue to take too long to load to provide an acceptable user experience for Media Viewer as a default feature, as shown on low-traffic category pages like this one . If an image has not been previously viewed by another user, it can take 5 to 10 seconds to load the full image, during which you have to watch a blurry thumbnail. This doesn't match user expectations of 1-2 seconds per image, as typically provided on top multimedia sites.
#8 Media Viewer
#301 Pre-render thumbnails on the back-end