There were a few problems that I noticed.
1. You aren't waiting in your loop at all. Please use
in your game loop so that you aren't hogging the CPU.
2. The pixels array is never used so why are you even reading the pixels?
3. Don't use underscores in the numbers. This makes it so that only people with Java 1.7 and higher can run your program (correct me if I'm wrong, it may just be that you can't compile it if you have a lower version than 1.7)
4. Why is your BufferedImage 4 times the window size? In your render method it says that it's so you can fit more tiles on the screen!? Just make your tiles smaller!