I find one of the hardest things to find out there somewhere is free pictures for my websites. I will admit, I would prefer to not pay anything if it is possible.
These sites offer a wide variety of quality pictures. If you use the similar site add on (You can find that at Finding Websites for Research) as well it makes hunting down free pictures much easier.
Once you find your pictures, sometimes editing can be a little difficult so it's nice to be able to find other online sources that are free as well.
I think the real trick to any of this is finding the ones that are both user friendly and effective!
I believe the sites I have directed you to can help you rather then hinder you.
Hope this helps! Throw down a like if it does!
Invest Yourself!
Invest Time and Passion.
You will Succeed!