there's an even easier method and the screenshot automatically shows up on your desktop. install filecatcher on your Mac and autosnap on your iPhone, also from Erica. go to the screen you'd like a screenshot of, run filecatcher and log in with terminal to your iPhone and run "autosnap" and voila, the screenshot is now on your desktop.
Correct me if I am wrong but i didnt think that dock or screenshot(from installer app) lets you take screenshots while you are touching the iphone.
For example if you wanted to take a screenshot of a Settings category highlighted in blue you could touch the iphone highlighting the category then run screenshot from the ssh command line while still holding your finger down.
This is useful for creating tutorials on how to use different apps etc etc.
OP- why would you want to make this more difficult than it is?
Were you simply unaware of the 3-4 programs that have been available on installer for quite some time?
the autosnap method automatically recovers the image from the iPhone onto your desktop. what screenshot program for the iPhone automatically places the image onto your desktop? as far as i know, you still have to ssh into the iPhone and download manually the photos from the iPhone file directory.