I was adding some new images and my sortorder in the gallery configuration (albums) is title-ASC (which works properly) and for all the images ID-DESC. I set no album manually to any other kind of ordering.

It seems that all my images now are ordered Title-DESC. I guess this is a small bug.
I'm using version 1.2.2.

There is a problem in 1.2.2 (and earlier versions) with the inheritance of gallery sort options. This has been corrected in the nightly build.