In layman's terms OLE Automation is a communication link between your application and another application.
In your case it would be YOUR application accessing and controlling the WEB CAM application.
You may not need to access the web cam application...perhaps just the dll's, but Christiaan is right, if you don't understand OLE Automation then you need to read some articles on the topic because this will be the best way to accomplish your goals.
That's the best link between the app's... The other (workaround) link I mentioned is to have YOUR application scan the saved image directory (maybe once every five minutes) for new images, process those images and then delete them from the directory.
At lot of web cams now have a feature where they will start recording if they detect movement. Set it up to do this, save the image to a directory and then your application will pick it up when it does it's next scan on the directory.
But in the long run this solution will be a lot more work as you will probably have to resize the image, change the format, brighten it...whatever. All these can usually be done in the WEB CAM application which takes us back to OLE Automation.
Another problem with this workaround is no matter how careful you are you'll find yourself running YOUR application but not the WEB CAM application... which means you'll have the whole thing running all day only to find out when your shutting everything down that you've got no images. OLE Automation would automatically open the WEB CAM application for you.
Yes,it would be possible to do a Process Start from your VB.Net app to fix this but that's another workaround that presents more work and more pitfalls.
Good luck.