I found that I can't set the sorting order to ascending. At admin, even the image_sortdirection set to zero, the descending check box still checked.

On front end page, I have an album always in descending order whatever the image_sortdirection is, but in other album is not. So, I tried to set both album to same value: sort_type = Date, subalbum_sort_type = Date, sort_order = null, image_sortdirection = 0, album_sortdirection = 1. The sorting result is different, I suspect the parent sorting function might mess up something.

Just tried on 12-14 nightly build

Yes, you are correct. This will be corrected in tonight's build.