<p>I am evaluating VintaSoft .net control and Atalasoft DotTwain Image Capture. And I am very but very lost with the most of the definitions and keywords.</p>

<p>So I am asking this because I think I am in Lala land. Is it possible to listen or have the scanner tell my app that there is a scanned image and I can process it?</p>

<p>The idea is to have a winservice that is waiting for the scanner to scan something and when that happens process the image.</p>

[edit - if it was me, I'd look at adzm's answer ;-p]
As I understand it, regular TWAIN is a "pull", not a "push" from the scanner. I could well be wrong...
I expect such interfaces do exist for high end, high volume scanners (you know, the ones the size of a billiard table) - but not (AFAIK) for regular consumer scanners.
For use with .NET (and before that, COM), I've always managed with
ImageMan
.