Question: Apologies if this has already been covered. It seems redirecting/rewriting URLs is easy, hosting PHP is easy, but redirecting PHP on IIS is a bit of a pain. Basically I am trying on a IIS server to redirect requests for any php page to default.aspx

I believe the main problem is that out-of-the-box IIS doesn't want to serve PHP.

Steps that I covered so far include 

* Writing a rewrite rule that does a regex match on any php file and pass it to default.aspx
* Adding \*.php to the handlers and using the same one defined for \*.aspx
* Restarting the server
* Hitting head against brick wall

I don't want to have to install FastCGI or equivalent just to do this - I just want to be able to handle any php pages that used to reside on the domain and point them at default.aspx

Any suggestions/advice welcome!

Answer: 
This is a URI scheme (Uniform Resource Identifier scheme) that provides a way to include data in-line in web pages as if they were external resources. 

See here <http://en.wikipedia.org/wiki/Data_URI_scheme> for a longer description.

You can encode your own here:

<http://webcodertools.com/imagetobase64converter>
It's the [data URI scheme](http://en.wikipedia.org/wiki/Data_URI_scheme), it is a way to provide the actual content of the resource in the URI (instead of the location where to find it).

There are example code on how to generate them in the linked wikipedia page, but as you can see in the sample you gave it's pretty easy to generate one; give the mime type, the encoding used and then the content.