Centre alignment in CKEditor 4.10 toolbar is disabled when selecting image inserted in the editor

I am using CKEditor version 4.10 in an mail delivery system project for composing emails. I have added justify plugin to get the justify tools in the toolbar. Since this is an email composing, user may want to align the contents(including images inserted) as Left, Right, Centre etc. But even though I can choose Left and Right align buttons in the toolbar after selecting the image, I cannot choose centre align button because it is disabled. Does anyone know how can I enable the centre align button on selecting the images inserted in the editor and can able to align the same in centre too ?