"Download Current View" downloads the viewport, not the screen

[respinos]

Description:

Originally, the scanned image viewport was shorter than the window height. In the current implementation, it's taller and scrolls with the page. Download Current View does not work as documented --- it downloads the full viewport, not the shorter rectangle represented in the visible window.

Acceptance Criteria:

• take into account the window dimensions when calculating the image rectangle
• or punt and remove the option