Screen Captures

I read Dave Mozealous Word of Mouth article from Jan 2009 (How to Get Perfect Screenshots in Presenter '09) and have been trying to interpret the information. I want to ensure consistent screen captures in terms of size to ensure that, no matter where used (PPT, Presenter, etc.), there is not that annoying jumping or nudging on the screen.

So I read where the optimum pixle window is 720x540. We are using Sizer or Snipping Tool to capture the image in that pixle size or smaller. Then Dave's article explained to save as PNG, gather data about the PNG properties and use the formula tool in his article to convert pixles to inches. Then override PPT need to resize by converting the graphic back to its appropriate size for the pixles....

Ok, I am feeling like I am missing something, or maybe it is my cold meds influencing me.... but a 720x540 is HUGE (10 in x 7.5 in).... my actual picture is not that large on my screen.... and it looks grainy and yucky!

I am wondering if the tools I am using override the need to follow all of the steps inside of Dave's article..... I just feel like this non-graphics person is really missing something! Thanks for any help.