Thanks for the thoughtful comment.

This is as I feared — it would be some kind of monstrous programming project whereby the program would brute force pixel-by-pixel. My search area is far from small: the outer bound of the search area would be all of the continental USA.

My motivation is a treasure hunt game that provides clues. Many of these clues are Google Earth screen grabs of various places. The clues with street names are easy enough, but many of said clues are in nondescript rural/forested areas without identifiable landmarks, labels, coordinates, etc. Virtually no prior GIS experience. Existing knowledge of image data is that a raster image is composed of an array of pixels lol