I don't see the image in internet and in my pc (Help line)

Hello!
I'm an italian User
Sorry for my bad english :D

I have problems whit the Png File extension.
I don't see the image in internet and in my pc(Help line)
This is an example


I downloaded the PNG extension, I have added to the registry, but nothing happens:huh::huh:.

What can i do?
Many thanks for your work!