Firstly, imho, a highly voted question should not be trashed lightly.
In the present case, changing the screenshot wouldn't change anything in essence, and including a Ubuntu screenshot would not make it more on-topic.
Now, it's not Ubuntu-specific, it's not Windows-specific, nor Mac OS, Solaris, SG/Irix, AIX, HP-UX, DEC Alpha, PDP-11 or whatever system specific, and it's not a developer question. However, it's clearly computer-related, and interesting to the community, and as such it's acceptable here.
AFAIK, there's no place for system-neutral, computer-related, non-developer questions on SE, and I'm not sure such a place should exist anyway, because there would be too many people posting system-specific questions there, thinking it's system-independent. Which means such questions should be accepted on any system-specific place where they appear. Imho, of course.
EDIT : It seems I was essentially wrong, since :
There's a place for such questions, Super User being for whatever computer-related doesn't explicitly fit anywhere else.
Off-topic questions are moved (with their answers), not deleted, which was another concern of mine sincebecause the question had quality answers already
Hence, my answer has changed, and I suppose that question could be moved to Super User without harm.