Query string makes problem in page loading

I know this, but why this works while first and usual way doesn't work?

The two dots indicate the parent folder; in other words, to go up a level.

Here's the code for that link:
        ImageUrl="~/Data/rabbit-icon.png" />

note that first that default page loads it has ~/Default.aspx address.

after I changes "~" to ".." it worked ! Why ?
        ImageUrl="../Data/rabbit-icon.png" />

I think that the part of your question asking "What is tilde" is the most important part of your question and people are not seeing that; I don't understand why not. There are others that can answer that question bettr than I but the tilde indicates the directory that is the root for the domain; the directory that your site should consider to be the root directory. Or something like that. So try using href="~default.aspx/?param=value".