Split out sticker CSS

src/skins/vector/css/_components.scss

@@ -48,6 +48,7 @@
 @import "./matrix-react-sdk/views/messages/_MEmoteBody.scss";
 @import "./matrix-react-sdk/views/messages/_MFileBody.scss";
 @import "./matrix-react-sdk/views/messages/_MImageBody.scss";
+@import "./matrix-react-sdk/views/messages/_MStickerBody.scss";
 @import "./matrix-react-sdk/views/messages/_MNoticeBody.scss";
 @import "./matrix-react-sdk/views/messages/_MTextBody.scss";
 @import "./matrix-react-sdk/views/messages/_RoomAvatarEvent.scss";

src/skins/vector/css/matrix-react-sdk/views/messages/_MImageBody.scss

@@ -18,11 +18,3 @@ limitations under the License.
   display: block;
   margin-right: 34px;
 }
-
-.mx_MImageBody_thumbnail_container {
-  display: inline-block;
-}
-
-img.mx_MImageBody_thumbnail {
-  max-width: 100%;
-}

src/skins/vector/css/matrix-react-sdk/views/messages/_MStickerBody.scss

@@ -0,0 +1,48 @@
+/*
+Copyright 2018 New Vector Ltd.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+.mx_MStickerBody {
+  display: block;
+  margin-right: 34px;
+  min-height: 110px;
+}
+
+.mx_MStickerBody_thumbnail_container {
+  display: inline-block;
+  position: relative;
+}
+
+.mx_MStickerBody_thumbnail {
+  max-width: 100%;
+  transition: 500ms;
+  opacity: 0;
+}
+
+.mx_MStickerBody_thumbnail_visible {
+  transition: 500ms;
+  opacity: 1;
+}
+
+.mx_MStickerBody_placeholder {
+  position: absolute;
+  transition: 500ms;
+  opacity: 1;
+}
+
+.mx_MStickerBody_placeholder_invisible {
+  transition: 500ms;
+  opacity: 0;
+}