Fixed NSFW image blur spilling outside the preview

* Hide overflow of wrapping picture element
  to contain the blur of the inner img element.
* This aligns the visible image area to the
  clickable area.
* fixes #1245

src/assets/css/main.css

@@ -434,3 +434,6 @@ br.big {
 em-emoji-picker {
   width: 100%;
 }
+.overflow-hidden {
+  overflow: hidden;
+}

src/shared/components/common/pictrs-image.tsx

@@ -22,7 +22,7 @@ export class PictrsImage extends Component<PictrsImageProps, any> {
 
   render() {
     return (
-      <picture>
+      <picture className="d-inline-block overflow-hidden">
         <source srcSet={this.src("webp")} type="image/webp" />
         <source srcSet={this.props.src} />
         <source srcSet={this.src("jpg")} type="image/jpeg" />