Image manipulation in asp.net/c# without System.Drawing/GDI+

Question

Is there any alternative image manipulation library for .net? I would prefer something that is managed and open source.

I ask this because of two reasons:

Answer 1

Anecdotal evidence #1: I have used GDI+ for on-the-fly image creation within ASP.NET with no problems. I'm not sure what the problems would even be.