Why Do My Photos have black bars going through them or totally black?

Recently I've been using Windows Movie Maker 2012 (16.4.3503.0728) and I map. I haven't had this problem before with any of my old animations but, for some odd reason, there are black bars going vertically through the screen or covering it. I've checked with the photos with my Photos app and it's not there. I don't know if it's because I'm using Windows 10, the resolution is to big, or something else. Will this affect my video at all, or is just in the editing panel? If anyone can tell me what's causing this or how to resolve it I would be grateful. Thank you for your time and patience.