IOS:UIImage
A UIImage object is a high-level way to display image data. You can create images from files, from Quartz image objects, or from raw image data you receive. The UIImage class also offers several options for drawing images to the current graphics context using different blend modes and opacity values.
Resizable Image
이미지를 안드로이드의 9patch처럼 늘리는 방법은 아래 메소드를 이용하면 된다.
[[UIImage imageNamed:@"bar_music_progress_all.png"]
resizableImageWithCapInsets:UIEdgeInsetsMake(34, 16, 36, 17)];