The first step:
1, click Image.xcassets to enter the image management, then right click, pop Up "New Launch image"
2, the right side of the check can let you choose whether to ipad, horizontal screen, vertical screen, as well as the lower version of the iOS system to do support. I chose IOS8.0,IOS7.0,IOS6 this way. No support.
Step Two:
Drag a specified size picture from your file to a fixed position
You can also click on the blank image to the right to see the size
Step Three:
Click your entire project name, and then select General
Here's the point.
I completed the above steps, and set the launch Images srouce for Launchimage, but the start picture is still the same, and later found launch Srceenfile, this inside set up, go to see, Your directory has a file called Launchscreen.xib Open the Right box, select the file, and then, the use as launch Srceen canceled, this is the reason you have been set launch image is not successful
iOS8 Xcode6 setting launch image start picture