OK, to the truth, I don't even know when how long the problem of changing wallpaper started on my computer until yesterday. The problem is that when I go to the 'Display Properties --->Desktop' and choose browse, I notice that I can't choose JPEG pictures . Note that I still can choose BITMAP pictures. Usually in the past, I can choose both of them. So, are there any method to recover my problem, please inform me! Thanks in advance.