Always set previousBackground to the current image
Always set previousBackground to the current image

If the form resize happens first, we don't want multiple copies of the
same image being created unnecessarily.

ROMaster2/LiveSplit,stoye/LiveSplit,Fluzzarn/LiveSplit,chloe747/LiveSplit,zoton2/LiveSplit,ROMaster2/LiveSplit,Jiiks/LiveSplit,Dalet/LiveSplit,Glurmo/LiveSplit,Dalet/LiveSplit,stoye/LiveSplit,kugelrund/LiveSplit,LiveSplit/LiveSplit,Glurmo/LiveSplit,kugelrund/LiveSplit,Jiiks/LiveSplit,Glurmo/LiveSplit,chloe747/LiveSplit,zoton2/LiveSplit,Fluzzarn/LiveSplit,Fluzzarn/LiveSplit,Jiiks/LiveSplit,PackSciences/LiveSplit,PackSciences/LiveSplit,zoton2/LiveSplit,stoye/LiveSplit,PackSciences/LiveSplit,chloe747/LiveSplit,kugelrund/LiveSplit,ROMaster2/LiveSplit,Dalet/LiveSplit