Scrollbar looks like is lost the position on huge image

[mykola]

Hi,

I have attached one huge PNG image. To reproduce the issue that I'm talking about just do the following:

1. Open image for preview.
2. Zoom to original size. Press "1:1" icon on toolbar.
3. Try to drag the scroll down and release somewhere in the middle of the image.
4. Scrollbar pointer moved back to the original position but at the point that I released the mouse.