Merge pull request #2853 from Raven24/publisher-images

fix shifted image button in firefox [ci skip]

public/stylesheets/sass/application.sass

@@ -773,17 +773,17 @@ form p.checkbox_select
 
     :display inline-block
 
-    :padding 0.3em
+    :padding .3em .3em 3px
     :cursor pointer
 
     img
       @include opacity(0.4)
-
+      :vertical-align bottom
       :display inline-block
       :margin 0
       :padding 0
       :margin
-        :bottom -3px
+        :bottom 1px
 
     &:hover
       :background
@@ -2820,4 +2820,4 @@ a.toggle_selector
   :font-size smaller
   :color #999
   a
-    :color #666
+    :color #666