Problem with pictures loading in Facebook

Hello,
I have an issue with Facebook on my mac - the thumbnails of the profile pictures and the chat pictures are not loading at all (they remain blank). I tried to login into my Facebook account using Safari, Chrome and Firefox and I had the same issue. I cleared the browsing data and cache, but I still have this problem.
I tried to load Facebook on my smartphone (Samsung Galaxy Y Pro) that I use regularly to check my messages and I experienced the same problem.
I decided to login on another PC and there I did not experience this issue, which is strange..
I then decided to login into a different account on my Mac and I experienced the issue again, so it is probably related to my Mac. But I do not understand why I have the same issue on my smartphone.
Any suggestions?
Thanks,
Jossif