I use the increase canvas size option a lot, just gotta crop you image to full size first and put your colored layer at the bottom, only thing I hate about it is if you use shapes to create a colored backdrop your have to go through and rastersize you layers first.
"If you get hit and it hurts hit him back you not knocked out yet."-Joe Doerksen
The Toxic Terrors (FFL)
Demetrious Johnson*Eduardo Dantas*Rafael Silva*Zach Makovsky*Michael Page