Is there a way to change the background color of the xcassets view in Xcode 5 or Xcode 6?
A reasonable work around is to select the image asset, (eg click on the 1x or 2x version) and then press the spacebar.This will show the asset in a popover with a light grey background.
If you are happy to add an Xcode plugin (it's available via Alcatraz) then TOCAssetCatalogBackground solves this problem. https://github.com/toco/TOCAssetCatalogBackground
Are the images essentially silhouettes? If so, you could make them in another color (I like to use magenta, because then it’s immediately clear when something isn’t working). Then you can use iOS 7’s -[UIImage imageWithRenderingMode:] (not sure if there is a Mac equivalent) to have the image automatically pick up the tint color of its containing view. Then you would not be looking at white images on a white background.