WPF application fails with "bad image format"

I have an application build on my x64 computer. It is now build for x86 but on windows XP machines (x86) it fails with th开发者_开发百科e "bad image format". On all Vista and up OS, it runs perfectly on x64 platfomrms. I tracked the problem to my icon.

I removed the icon and now it runs fine, anyone got an idea of how on earth this could relate to anything?

This error is basically telling you that a dll being loaded does not match the bitage (32 or 64) of the process. You could be loading up an assembly using native 64bit code, or it could be a single dll that is set to x64. You can use the corflags utility from the Visual Studio Command prompt to check what the .NET assembly bitage is set to.