Take the following with a big grain of salt since I've not used the WinForms Designer since VS2010. I believe that if you try to set the icon for the form with a custom icon, or put in a picture box with a custom picture, the Designer will automatically create the .RESX file for you. Or you could just explicitly add a resource to the project and it'll also create a .RESX file for you, but I think it'll be ProjectName.resx, instead of Form1.resx.