I'm running Umbraco 4.5.2 beta (.NET4) on IIS7, the problem also exists in 4.5.1 and probably earlier versions as well.

The Umbraco installation (clean, no modifications) is set up as a sub-application in IIS (the parent application is empty (no files at all) so it shouldn't affect the sub-app):
So the URL to the root is like this: http://example.com/mysubweb/

When inserting links to media there is a problem with the URL-resolving.

For example, when inserting an image, the URL in the dialog (after picking the image) will be "/mysubweb/media/1234/Image.jpg", and the image shows up as expected in the WYSIWYG editor (Richtext editor (TinyMCE v3)).
But when you save the page the URL is saved to the database as "/media/1234/Image.jpg".

But I don't think that's the actual problem, because in the background I guess it would be fine that it points to the root there, but the actual problem is that it doesn't translate into the correct URL at render time.

So when the page is rendered the URL to the image will be "/media/1234/Image.jpg" and it won't be found (correct should be: "/mysubweb/media/1234/Image.jpg").

And it also doesn't show up correct in the WYSIWYG editor because of this.

If I try to change the URL to this: "~/media/1234/Image.jpg" by editing the HTML in TinyMCE, it will remove "~", so that will not work.

There is a similar problem when linking to a media.file.

Linking to a document using the dialog will result in a URL like this: "~/media/4321/Document.pdf".

But when TinyMCE receives this (I guess) it adds / to the beginning of the path, so at render the path will look like: "~/media/4321/Document.pdf".

So, am I doing anything wrong or is this a bug?

Shouldn't for example src="/media/123.jpg" be resolved to "/mysubweb/media/123.jpg" ?