tweak event item image sizes to fix low image quality on mobile

web/src/components/events/EventItem.tsx

@@ -11,7 +11,6 @@ import {
 import {
   formatDate,
   formatDateRange,
-  formatExtendedDateTime,
   groupConsecutiveDates,
 } from "@/lib/date";
 
@@ -47,7 +46,7 @@ export const EventItem = ({
             alt={featuredImage.alt}
             width={0}
             height={0}
-            sizes="20vw"
+            sizes="(max-width: 900px) 100vw, 25vw"
           />
         )}
       </div>