Add pixel background to modal images

app/assets/stylesheets/components.scss

@@ -288,10 +288,14 @@
   }
 }
 
-.transparent-background {
+.transparent-background, .imageloader {
   background: image-url('void.png');
 }
 
+.imageloader {
+  display: block;
+}
+
 .dropdown {
   display: inline-block;
 }