Implements -[NSImage isGIF] method to return whether current NSImage is GIF representation.
Implements -[NSImage isGIF] method to return whether current NSImage is GIF representation.

awkward/SDWebImage,smule/SDWebImage,zhang-yawei/SDWebImage,dreampiggy/SDWebImage,dreampiggy/SDWebImage,dpettigrew/SDWebImage,Insfgg99x/SDWebImage,altrooz/SDWebImage,dreampiggy/SDWebImage,iheartradio/SDWebImage,awkward/SDWebImage,rs/SDWebImage,awkward/SDWebImage,tualatrix/SDWebImage