Most of the images relatively small thumbnails. The 320 by 213 version of the previous image looks like this:
Click on the image above to open a window with just the original jpg file. We have also processed this image to upsample by 2x, which increases the 55 kilobytel original to 263 kilobytes, to upsample by 3x, which takes us to 496 kilobytes and to upsample by 4 which takes us to 792 kilobytes.
There is, I hope you will agree, surprising utility in the 4x upsampled image. This is not unexpected, because if the image was simply downsampled, it is the resolution is certainly sample limited and upsampling improves the display. The 4x upsampled image, of course, is not as good as the original full resolution image, which one can obtain for reference by clicking here.
There is relatively little use in tile server for such images, but if one wishes to just present a thumbnail, I hope that one will agree that the interactive thumbnail using the 4x upsampled version is more compelling than the static thumbnail shown above.
It is important at this point to carefully consider the set of different problems we can address. The classic problem of sending an image to a remote device using as little bandwidth as possible, while assuming that the remote device has ample computational resources, is best solved using classical compression strategies, e.g. jpeg2000 or mpeg. Super-resolution is most interesting in different scenario, where we assume real-time communication between the server and display and our goal is to maximize display speed and interactivity while minimizing display computational load.
Let's look at some more images.