How to add CKeditor Templates
It was hard to find the information but I succeed:


Copy ckeditor.config.js from the ckeditor module ( sites/all/modules/contrib/ckeditor/ ) to your theme ( sites/all/themes/MYTHEME/ ) 
Edit the ckeditor profile configuration in Drupal ( admin/config/content/ckeditor/edit/Full ): in ADVANCE OPTION, set Load ckeditor.config.js from the theme path to YES
Modify the ckeditor.config.js from your theme to add your custom template file:

CKEDITOR.editorConfig = function(config) {

config.templates_files = [ Drupal.settings.basePath +   'sites/all/themes/MYTHEME/js/ckeditor.custom.templates.js' ]; 
//...continue the config file

Copy your image template to sites/all/themes/MYTHEME/ckeditor-tpl/
In your JS theme file ( sites/all/themes/MYTHEME/js/ ) create a file ckeditor.custom.templates.js as following:

CKEDITOR.addTemplates( 'default',
{
imagesPath: CKEDITOR_BASEPATH + '../../themes/boson/ckeditor-tpl/' ,
templates :
    [
        {
            title: 'My template',
            image: 'my-template.PNG',
            description: 'Your custom template.',
            html: 'Hello world!'
        },
    ]
});



it works well for me. Hope it will help someone.