No, it didn't go through twice that I am aware of @viy lol!
As far as sourcing, it's simple, we attempt to get the original author, not the sharer or image hosting site; there are a number of royalty free sites like Pixabay.com and Unsplash.com, but sourcing not only puts some light on the original artist or photographer, but also sets the stage that you did not plagiarize or use anyone else's material without rights.
To answer the other question, the next few days are iffy because everything is still being worked out, and even without this HardFork going on, a lot of people have had comments accidently post twice, I think that has happened to the majority of us.
But you're good.