The odds are very likely it’s a new image, and yes, the option that I think would be useful is to download new images from the database, if my pictures are likely different. The images would be better because that’s what happens when images are replaced on the games database, they are replaced with more appropriate, more accurate pictures. The frequency that this is not the case is far more rare than when a new image is posted. When a new image is posted it has a much higher likelihood of being inaccurate or low quality, then times that someone replaces an image on the database, because they are consciously doing so with the intention that they are improving upon it. However as it is now when they do so nobody gets those images unless they choose to overwrite all of the images, including images where it is the same image.
Another way to think about this - why is there an option for me to override my current images with the same image? Can we have an option in the future to overwrite the images that are different from the images on the gamesdb.