Can I write a paper on a method that is novel but yields similar results compared to existing methods?
As your three-image method takes a new approach, it is novel in the academic sense: It adds to the existing knowledge. Thus you should be able to publish a paper on this, though probably not in a high-ranking journal (unless you blatantly underestimated the advantages of your method). The rationale for this is the following and you may use it to motivate your method in your paper: Your new approaches may inspire other methods which in turn may drastically outperform existing ones or yield entirely new information.

You could write the paper directly in this tone, not focussing on the method you are presenting but on the fact that you can extract the information your method (and the others) yield in a new way. In this context, you may consider not presenting your method primarily as a method, but as a way to verify your approach to extract the existing information.

You might get bonus points, if you actually have suggestions how to improve your method to outperform the existing ones.