Sometimes ago, I discovered an open source GDI+ Library built by Erik Van Bilsen. I now use that Library extensively with excellent result.
I used it to build an image processing system and other similar things.
The Library is intended for Delphi 2009 and above. I currently use it with Delphi XE4 with no problem.
It comes with a nice sample application that demonstrate the usage of GDI+ through examples which are Microsoft own samples translated to Delphi.
You can find more info at Erik Van Bilsen website.
The project is hosted on SourceForge at http://sourceforge.net/projects/delphigdiplus/
Microsoft home page for GDI+ is at http://msdn.microsoft.com/en-us/library/windows/desktop/ms533798(v=vs.85).aspx
Update: Sample application article at:
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