A number of members reported in Everything SG that recent SG photosets seemed to be blurry on the new site. We diagnosed the issue, and a background process is now going back and fixing all of the affected SG and hopeful albums to upgrade their image quality (by going back and copying different files from the old site than we originally grabbed). The newest SG albums will be tackled first, and the process will go backwards in time fixing all of the SG albums in reverse order of creation; after that, the same process will be applied to hopeful albums. All albums should be fixed within a day or two.
If you're the first person to view a given set since that set was fixed, then you might see the "SG" logo placeholders in place of all of the images. That triggers our thumbnailing process, so just wait a couple of minutes and refresh the page, and the photos will start trickling in. That will only happen once per album.