grunt-contrib-imagemin: JPG image optimization not working

When I use this:

            dist: {
                options: {
                    optimizationLevel: 3
                },
                files: {
                    '../dist/img': ['../images/**/*.*']
                }
            }

It won’t copy my jpg images and if I specify an jpg like this:

            dist: {
                options: {
                    optimizationLevel: 3
                },
                files: {
                    '../dist/img/email.jpg': ['../images/email.jpg*']
                }
            }

I get the following error:

Fatal error: ENOENT, no such file or directory ‘c:\proj\dist\img\email.jpg’