Users pictures are not showing

Fairly recent issue for moodle administrators beginners is problem about users pictures not showing. I call it "Yellow smileys hell". How to beat this devils and get pictures of our beautiful user to show and not to feel ashamed?

In most cases is problem in slasharguments settings.
in Site administration > Server > HTTP

You can identify this fairly easy. User photos aren't showing and when you try to access uploaded files you will be rewarded only by No input file error.

Try fiddle with this settings. And remember, sometimes (IE mainly) helps clearing the browser cache or forced refresh (CTRL + F5).