Thank you so much! I had to run only the above command to remove the two incriminated wallpapers from the imagehistory in my wallpaper selection dialog. I mean gconftool -u /desktop/meego/background/portrait/original_filename was not necessary. This maybe because, how I said before, I removed the wallpapers before with filebox from <home/user/wallpapers> and <home/user/MyDocs/wallpapers>.