Please consider following use case,

1. I have one bigger image, lets called is master image.
2. Now from some where else, I am getting one small image. I want to check whether this small image is subset of master image or not.

important points are, smaller image might have different file format, smaller image might captured from comparatively different view. smaller image may have different light intensity.

At this stage of algorithm/computation advancement, which level of accuracy I could expect?

Any algorithm/open source implementation that would have such implementation?

Thanks, Rajnikant