Under the "Is it okay to use random pictures from the internet?" section, you list several websites with free pictures. I think some of those sites have pictures that require attribution.
Does anyone who is familiar with the sites know what the polices are for each of the sites?
Pexels.com
Stockfreeimages.com
Unsplash.com
Pixabay.com
Freeimages.com
Maybe I'll take out the others and only use Pexels.com as the example? It is my favorite on the list. I will also add information on it being completely free to use with no attribution required.
Pexels website states:
"It's hard to understand complex licenses that is why all photos on Pexels are licensed under the Creative Commons Zero (CC0) license. This means the pictures are completely free to be used for any legal purpose.
The only restriction is that identifiable people may not appear in a bad light or in a way that they may find offensive, unless they give their consent."