Android :: Scrolling Large Image - Working Good But Slow

For a project, I'm displaying an image with sizes 800 x 600 and I've implemented my custom scrolling (horizontal and vertical) - which is works fine. However, my problem is that it's not fast enough. If you continuously move your finger on screen for instance, scrolling is not responding fast enough. There is a lag and you need to wait (say 400-500ms) for new scrolled image to be loaded. Now below I described how I implemented scrolling and my question is that
- How can I make it faster, if possible - Is there any other better way to implement this.

My custom scrolling solution:
* I have a Main activity, SurfaceView and a thread
* In main activity, I'm using GestureDetector and override onScroll method.
* In onScroll method of activity, I'm passing values to SurfaceView's "handleScrolling" method.
* In "handleScrolling" method, I'm calculating proper values and using "newImage = Bitmap.createBitmap(myImage, starX, stopY, SCREEN_WIDTH, SCREEN_HEIGHT)"; to create a new, "scrolled" image.
* Then in thread loop, I'm drawing this "newImage" to canvas.