Having used ubuntu for over 3 years, I switched to lubuntu today. I downloaded a photo from gmail inbox and it saved in the downloads folder. When I set it as wallpaper it appears upside down. I have tried it with a couple of other photos but no change. The standard lubuntu ones are fine. Has anyone got any ideas as there seems to be no option to change it? Many thanks, Ian.
My thought after hearing this is that the pictures that you are trying to set as desktop wallpaper contain some EXIF data that define their orientation.
While the photo ought to have been taken upside down, the EXIF data (that the camera included in the photo) inform your system that the picture was taken this way, and thus it displays the picture as it should be. This should be true for the file manager and for the picture viewer, in your case, but not for the application drawing your desktop.
My suggestion would be to open the picture in a program like Gimp, that will open it as is, and rotate it normally, then overwrite the original (or save it as a new image) and set it again as desktop background.