Hello Brandic329,
Welcome to Apple Support Communities. We understand that your Lock Screen is black no matter which image you select as your wallpaper.
Are the images that you have selected ones that were taken on this iPhone or another device? That will help us to determine if these photos are stored on your iPhone or somewhere else such as iCloud.
Try selecting a stock wallpaper and test to see if the same occurs. Is 'Dark Appearance Dims Wallpaper' selected from Settings > Wallpaper? If so, try disabling that feature as well. This feature is mentioned in Change the wallpaper on your iPhone.
Have a great day!