These size of the file is 156 KB and I'm using the Apache webserver.
Just when I was trying to figure out from which filesize the files wouldn't load, it suddenly started working again! I didn't change anything on the webserver.. so I can't explain why.
But this has happened before, and then the exact same thing happened. I installed and configured Apache, the images wouldn't load.. and then it suddenly started working. And now it's happening again.
So if anybody could explain to me why this is happening, I'd really like to hear it. Something tells me this will happen again in the future..