Transparent / Not Transparent

[MahaB82A]

You can see in the Ps workspace same image has different background which shows Transparent & Not Transparent background. It is clealy visible here. But in the Windows explorer both look same. How to differenciate this?

Also in some websites imge of a icon look transperent [white & ash square background] but it's downloded image does not show any trensperent. What is reason for that?    

[c.pfaffenbichler]

Also in some websites imge of a icon look transperent [white & ash square background] but it's downloded image does not show any trensperent. What is reason for that?    

Please post examples (both the links and screenshots of what you are getting). 

[MahaB82A]

When I come across next time I will post it.