"Classes within the System.Drawing namespace are not supported for use within a Windows or ASP.NET service. Attempting to use these classes from within one of these application types may produce unexpected problems, such as diminished service performance and run-time exceptions. For a supported alternative, see Windows Imaging Components."
System.Drawing actually wraps GDI win32 calls, so while it works, running it on a server would be iffy, and running it on non Windows would be impossible.
Now, they could reimplement system.drawing using a different backend per platform, but I don't think the demand is high enough.
Comments
Using System.Drawing from ASP.Net was never supported anyway (although much of it did work). From https://msdn.microsoft.com/en-us/library/system.drawing.aspx
"Classes within the System.Drawing namespace are not supported for use within a Windows or ASP.NET service. Attempting to use these classes from within one of these application types may produce unexpected problems, such as diminished service performance and run-time exceptions. For a supported alternative, see Windows Imaging Components."
System.Drawing actually wraps GDI win32 calls, so while it works, running it on a server would be iffy, and running it on non Windows would be impossible.
Now, they could reimplement system.drawing using a different backend per platform, but I don't think the demand is high enough.