Hi from France.
My new issue with NextGEN Gallery is visible here :
For one year, I didn't have any problem with the NextGEN Gallery widget. Now, I can no more set the widget with "All galleries" (or even "Only which are not listed").
The only setting which seems indeed to work is "Only which are listed" with some galleries indicated. My website counts nearly 163 galleries and thousands of pictures so I can hear that it's huge. I've desactived all the other plugins with no success. I have another website with far more less galleries and it works. So I fear that above a certain number of galleries or pictures, the widget can't handle the picking of "random" or "recent added" pictures.