Windows 7 – How to Change Desktop Background Rotation Time

Not that I know, but it can be fixed with an AutoHotkey script. For instance, this will use Win+n to go to the next desktop background:

#n::                             ; use the Windows+n hotkey
WinActivate, ahk_class Progman   ; activate the Desktop
MouseGetPos, xpos, ypos          ; get current mouse position
Click 0,0                        ; click in the corner of the desktop, to unselect any selected icon
Send +{F10}                      ; send Shift+F10, the shortcut for right-click
Send n                           ; send "n", the key for "next desktop background"
Click %xpos%, %ypos%, 0          ; put the mouse back at its previous position
return                           ; done!

The "n" in Send n is only valid for an English Windows 7 (Next desktop background). You'll have to change it if your Windows 7 is not in English to match the underlined key.

In my experience, there does not appear to be any native means of resolving this. Windows will assume that any wallpaper image intended to span multiple screens should originate from the top-left corner of the primary display, regardless of where the primary display is in relation to the others.

There are a couple ways to work around this. One, as suggested by @Petr, is to chop up the image in an image editor (e.g.: MSPAINT) and put the right half on the left and vice-versa. This can be a little tricky, especially if the image isn't at the same aspect ratio as your monitor or if you have monitors with different resolutions/ratios.

The other alternative is to get a program that will do it for you. There are several out there which will generate the image for you to set as your desktop background. I prefer DisplayFusion, which also offers a number of options for resolving other common multi-monitor headaches. DisplayFusion comes in Free and Pro editions, and the Free edition is totally free - no adware, spyware, or nagware.