Requesting a nice. lightweight alternative to Windows Photo Viewer, preferably something that can playback .gifs as well.
While I'm at it, I'm also looking for a similar tool for image management/sorting.
irfanview is probably one of the fastest most memory efficient viewers. Depending on what type of 'image management' you're looking for, it does basic shit like cropping, resizing, batch changes, etc.
Other programs to try are nomacs and xnview