Error "Invalid Parameter" fom ImageMagick convert on Windows

Question

I am trying to convert a PDF document into a PNG file using ImageMagick command line tools from a ASP.NET website. I create a new shell process and ahve it execute the following command:

convert -density 96x96 "[FileNameAndPath].pdf" "[FileNameAndPath].png" 

This runs well when testing the website on my local machine with the ASP.NET Develeopment Server of VS and the command also works well when manually entered into the shell. When running from the programatically created shell in ASP.NET there is the following error message:

Invalid Parameter - 96x96 

Does anybody know why that happens and what to do?

I have tested the command while being logged in on the server via RDP with a different user account than the ASP.NET process. I have used exactly the same ImageMagick and Ghostscript installation files as on my local machine and have activated adding the ImageMagick installation path to the enironment variables during installing. The server has not been rebooted since than.

Answer 1

convert is also the name of a windows executable which converts FAT filesystem to NTFS. When you do not specify the full path of an executable, quote:

...the system first searches the current working directory and then searches the path environment variable, examining each directory from left to right, looking for an executable filename that matches the command name given.

"C:\Windows\System32" is generally present in the beginning of %PATH% variable, causing the Windows convert utility to launch, which fails with "Invalid Parameter" error as expected.

Try specifying the full path of the ImageMagick's convert.exe like so:

"C:\Program Files\ImageMagick\convert.exe" -density 96x96 "path_and_filename.pdf" "path_and_filename.png"