Revert banner images to .png (files under size threshold)

Author: VelmiraS

.vitepress/theme/components/Banner.vue

@@ -1,8 +1,8 @@
 <script setup lang="ts">
 import { computed, ref, onMounted, onUnmounted } from 'vue'
 import { useRoute } from 'vitepress'
-import banner from '../assets/banner.webp'
-import bannerMobile from '../assets/banner-mobile.webp'
+import banner from '../assets/banner.png'
+import bannerMobile from '../assets/banner-mobile.png'
 
 const BANNER_EXPIRY = new Date('2026-03-27T00:00:00Z')
 const BANNER_LINK = 'https://neonephos.org/events/2026_03_23_KubeCon_Europe'

website/community/hackathons/2026-05.md

@@ -13,7 +13,7 @@ outline: 2
 - 🎤 **Review Meeting Summary:** https://gardener.cloud/community/review-meetings/2026-reviews/#_2026-05-13-hack-the-garden-wrap-up
 
 <div style="display: flex; justify-content: center; gap: 20px; margin: 24px 0;">
-  <img src="./images/2026-05_1.png" style="width: 49%; max-width: 100%;" />
+  <img src="./images/2026-05_1.webp" style="width: 49%; max-width: 100%;" />
   <img src="./images/2026-05_2.jpg" style="width: 49%; max-width: 100%;" />
 </div>
 ## 🌱 Complete the `ManagedSeedSet` Implementation ([#52](https://github.com/gardener/hackathon/issues/52))