>The answer is in the sample
>
>If TryGetValue() returns true, it was in
>
>There's also ContainsKey() - but TryGetValue() tells you whether the image was in and if it was returns the data via the out parameter
>
>http://msdn.microsoft.com/en-us/library/xfhwa508(v=vs.110).aspx

Thanks, so you would recommand TryGetValue() instead of ContainsKey(). Is that correct?