How does the League Displays randomizer work?

Hello, I've been using League Displays for a while now (the program from riot that changes your wallpapers automatically) and I downloaded more than 1.2k wallpapers (champs, art, events, videos, etc), but during the day I noticed that 9-10 images repeat between 4-5 times during the day, every single day. I'm getting a lot of wallpapers from the annie origin video. Is it suppose to work like that? Can you guys update it to be more random or something, or make something like if a wallpaper shows, it doesn't show anymore during the day, unless you already seen all of them? Thanks.