My apologies if I have misunderstood your intentions, Actually I want to take the Photoshop for any kind of Photo Editing jobs, because of the various functions offered this tool. I don't want to mention the only way to avoid others. I think there are lots of tuts belong to the topic.
Due to respect, scotty, As I know this is not the actual query from courtneywilkins He said low resolution images and make them into high resolution, I think we can try to make an advice using Photoshop, Because of the most common and useful tool.
There are 'better' tools out there for this job than photoshop at present, I vaguely remember reading about photoshop getting ai (artificial intelligence) tools at some point to help with this type of issue.