use shared image loader

dashboard-ui/bower_components/emby-webcomponents/images/basicimageloader.js

@@ -0,0 +1,25 @@
+define([], function () {
+
+    function loadImage(elem, url) {
+
+        if (elem.tagName !== "IMG") {
+
+            var tmp = new Image();
+
+            tmp.onload = function () {
+                elem.style.backgroundImage = "url('" + url + "')";
+            };
+            tmp.src = url;
+
+        } else {
+            elem.setAttribute("src", url);
+        }
+
+        return Promise.resolve(elem);
+    }
+
+    return {
+        loadImage: loadImage
+    };
+
+});