* @ngdoc method
    * @name umbraco.services.tinyMceService#createMediaPicker
    * @methodOf umbraco.services.tinyMceService
    *
    * @description
    * Creates the umbrco insert media tinymce plugin
    *
    * @param {Object} editor the TinyMCE editor instance        
    * @param {Object} $scope the current controller scope
    */
    createMediaPicker: function (editor) {
        editor.addButton('umbmediapicker', {
            icon: 'custom icon-picture',
            tooltip: 'Media Picker',
            onclick: function () {

                var selectedElm = editor.selection.getNode(),
                    currentTarget;


                if(selectedElm.nodeName === 'IMG'){
                    var img = $(selectedElm);
                    currentTarget = {
                        altText: img.attr("alt"),
                        url: img.attr("src"),
                        id: img.attr("id")
                    };
                }

                userService.getCurrentUser().then(function(userData) {
                    dialogService.mediaPicker({
                        currentTarget: currentTarget,
                        onlyImages: true,
                        showDetails: true,
                        startNodeId: userData.startMediaId,
                        callback: function (img) {

                            if (img) {

                                var data = {
                                    alt: img.altText || "",
                                    src: (img.url) ? img.url : "nothing.jpg",
                                    id: img.id
                                };

                                editor.insertContent(editor.dom.createHTML('img', data));

                                $timeout(function () {
                                    var imgElm = editor.dom.get('img.id');
                                    var size = editor.dom.getSize(imgElm);

                                    if (editor.settings.maxImageSize && editor.settings.maxImageSize !== 0) {
                                        var newSize = imageHelper.scaleToMaxSize(editor.settings.maxImageSize, size.w, size.h);

                                        var s = "width: " + newSize.width + "px; height:" + newSize.height + "px;";
                                        editor.dom.setAttrib(imgElm, 'style', s);
                                        editor.dom.setAttrib(imgElm, 'id', null);

                                        if (img.url) {
                                            var src = img.url + "?width=" + newSize.width + "&height=" + newSize.height;
                                            editor.dom.setAttrib(imgElm, 'data-mce-src', src);
                                        }
                                    }
                                }, 500);
                            }
                        }
                    });
                });


            }
        });
    },

This fixes the problem in 7.2.8, I suspect it'd work on earlier versions too.