I've changed a lot of mine. To be honest, Unsplash *should* be fine. The crediting is automatic, so it's the safest option in my opinion. I still use some Unsplash photos, but I've started using 100% my own on new articles since writing this. And yes, sometimes they're not quite right... but you know what? My reads are up. I guess the pictures are not that important. Perhaps there's merit in using your own pics because they're different to the same old stock that everyone else is using.