Pictures deleted 4+ years ago randomly back in my photo library??

Hello! So long story short, I deleted these pictures at least 4+ years ago and I went into my pictures and I saw about 30 of them. I’m the type of person who doesn’t have a huge photo library, just around 200 pictures, so it was easy for me to notice these new additions. I’ve never had this happen before so I’m not sure if this is just a glitch or if something happened?