Uploading Personal Poster Collection

What is the best way to replace a poster image that gets imported from Poster Vault. It works sometimes and other times it doesn’t. The way I do it is renaming the desired poster filename the same as the imported one from Poster Vault, then clicking upload and let it overwrite the file. I am replacing the imported posters for Kaleidescape. For example, I successfully replaced Predator: Badlands but Tron, the original 1982 movie, doesn’t want to accept it. As a matter of fact, the now playing poster was an entirely different movie the first time I imported it. The second time, it showed Tron: Ares. After cleaning the folder a third time, it correctly imported the right poster but still won’t let me replace it. Some questions I have are…

Is there a resolution limit?

Is there a naming convention?

Is there a cache that might be interfering and a way to clear it?

Is there a proper way to replace an existing poster image?

Is there an option to get the software to auto-scale the image to fit the Frame TV? There are some posters in my collection with varying resolutions and aspect ratios so some will overscan.

I have a vast poster image collection I have proudly invested much time and money into since 2010. I have many original digital versions of posters including ones I have cleaned up with Photoshop. Many are original high resolution text based posters. The great news is that the Plex Service imported every single poster from the movie library on my Plex Server. It shows every one correctly with now playing. It’s a joy to watch them using the Plex Movie Folder for playback.