I found that Ghostscript is able to convert PDF to Image format.
I tried PDF to Image Converter but not able to understand it clearly.
I have installed
Why do you try to add the library as reference to your project? gsdll32.dll is a native dll, not a Dot-Net library.
When I build the sample project using Visual C# Express 2010 I get an exe file. If I execute it it tries to access the gsdll32.dll. The problem is now that on a 64bit system a 64bit executable is generated but the gsdll32.dll is compiled for 32bit.
The correct solution would be to modify the source code and replace gsdll32.dll with gsdll64.dll everywhere it occurs. The simpler solution is to use the 64 bit version of Ghostscript, copy the gsdll64.dll into the same directory as the ConvertPDF.exe and rename it to gsdll32.dll. This definitely works - just tested and converted a PDF to TIFF.