Losing quality while uploading

Hello, I am struggling with a problem that my jpg. files loses quality while uploading to A-P.net. It gets very soft and the vibrance gets weird! Is this only a problem that I have if so how to fix it? It might just look so from my computer? Please tell me what you see! :)

compare it to this one: http://sv.tinypic.com/view.php?pic=2h3766a&s=8#.VYwCjrnqF9A

As you can see the file lost quality:

Thanks for the help!

Attached photos:

Hi,

the one you uploaded to AP is a bit darker and the clouds look a bit purple compared to the one you uploaded to tinypic, Sharpness looks the same to me.

Rgds,

Gerard