<p>I want to be able to compare an image taken from a webcam to an image stored on my computer.</p>

<p>The library doesn't need to be one hundred percent accurate as it won't be used in anything mission critical (e.g. police investigation), I just want something OK I can work with.</p>

<p>I have tried a demonstration project for <a href="http://www.codeproject.com/KB/cs/BackPropagationNeuralNet.aspx" rel="noreferrer">Image Recognition from CodeProject</a>, and it only works with small images / doesn't work at all when I compare an exact same image 120x90 pixels (this is not classified as OK :P ).</p>

<p>Has there been any success with image recognition before?</p>

<p>If so, would you be able to provide a link to a library I could use in either C# or VB.NET?</p>

You could try this:
http://code.google.com/p/aforge/
It includes a comparison analysis that will give you a score. There are many other great imaging features of all types included as well.
```
```
// The class also can be used to get similarity level between two image of the same size, which can be useful to get information about how different/similar are images:
// Create template matching algorithm's instance

// Use zero similarity to make sure algorithm will provide anything
ExhaustiveTemplateMatching tm = new ExhaustiveTemplateMatching(0);

// Compare two images
TemplateMatch[] matchings = tm.ProcessImage( image1, image2 );

// Check similarity level
if (matchings[0].Similarity > 0.95)
{
    // Do something with quite similar images
}
```
```