I believe as copyright holder the originator of the work can do what they like to it. What the CC license says is that the image that has been posted is CC licensed for all people to use under that restriction. As originator you can license it in different and multiple ways though a user can choose which one he would like to use. I.e. you could publish two images, one high res with an NC and a lower res version with commercial permissions. Only if you disclaim copyright and make the image public domain do you lose any control over the image. What a CC license does is grant permissions so that any user can use it in that way without needing to ask for copyright holders specific permission. What CC also does is prevent the originator from prosecuting for a users use of the file if he uses it within the terms. And if those terms include a redistribution clause - the SA bit - then it serves as a protection for people using the image when posting it up on a web site. A CC license is still just a license. You still own the original and are free to license it under any terms you feel like.