[colonwqbang]

Based on my understanding, the patent still needs to represent an "inventive step" from the prior art. Let's say you can show that

A. Classifying images based on a (pre-existing?) identification; B. Filtering images based on classification; C. Wirelessly transmitting images

were all known at the time. Then you could argue that a "person having ordinary skill in the art" would have known to combine A+B+C to solve the problem. Thus the prior art teaches the invention and the patent should be declared invalid.

[pkilgore]

This isn't wrong. But it's oversimplified and in practice in the US obviousness arguments have a low likelihood of success, lower if it gets too a jury trial.

You are much better off defending again infringement suits with novelty arguments.