Why am I getting no pic with Arduino Uno and OV7670 ?

Why am I getting no pic with Arduino Uno and OV7670 ? All that I get is just one line at the bottom. Look at the bmp file I got after adding the bmp header. What does just one white line at the bottom mean ?
How to check if the camera is working or not ? Any test programe ? Arduino uno is working with other simple programs.

test.jpg

A very demanding project!
There can be many problems with wiring and power (5V Arduino, 3.3V OV7670).An interesting introduction: