diff --git a/web/pageComponents/shared/Teaser.tsx b/web/pageComponents/shared/Teaser.tsx
index 7590023c4..31bbedeb7 100644
--- a/web/pageComponents/shared/Teaser.tsx
+++ b/web/pageComponents/shared/Teaser.tsx
@@ -39,6 +39,7 @@ const TeaserImage = ({ image }: { image: ImageWithAlt }) => {
           style={{ objectFit: 'cover' }}
           fill
           role={image?.isDecorative ? 'presentation' : undefined}
+          sizes="(max-width: 750px) 100vw, (max-width: 1200px) 50vw"
         />
       )}
     </>