diff --git a/src/components/views/messages/MImageBody.tsx b/src/components/views/messages/MImageBody.tsx
index 1e9678dbef..a4a615fa65 100644
--- a/src/components/views/messages/MImageBody.tsx
+++ b/src/components/views/messages/MImageBody.tsx
@@ -439,7 +439,7 @@ export default class MImageBody extends React.Component<IProps, IState> {
     }
 
     // Overidden by MStickerBody
-    protected getPlaceholder(width: number, height: number) {
+    protected getPlaceholder(width: number, height: number): JSX.Element {
         const blurhash = this.props.mxEvent.getContent().info[BLURHASH_FIELD];
         if (blurhash) return <Blurhash hash={blurhash} width={width} height={height} />;
         return <div className="mx_MImageBody_thumbnail_spinner">