perf: replace offline mode images

Co-authored-by: Isaac Saunders <contact@eartharoid.me>

src/components/widgets/background/Background.jsx

@@ -52,7 +52,7 @@ export default class Background extends React.PureComponent {
     ];
 
     this.setState({
-      url: `./offline-images/${randomImage}.jpg`,
+      url: `./offline-images/${randomImage}.webp`,
       photoInfo: {
         credit: photographer
       }

src/components/widgets/background/offline_images.json

@@ -1,20 +1,32 @@
 {
-  "Tirachard Kumtanom": {
-    "photo": [1]
+  "Ryan Hutton": {
+    "photo": [2]
   },
-  "Sohail Na": {
+  "Francesco De Tommaso": {
+    "photo": [3]
+  },
+  "Andy Vu": {
     "photo": [4]
   },
-  "Miriam Espacio": {
+  "Kevin Kurek": {
+    "photo": [5]
+  },
+  "Frank Mckenna": {
+    "photo": [6]
+  },
+  "Yuriy Bogdanov": {
     "photo": [7]
   },
-  "Fabian Wiktor": {
-    "photo": [20]
+  "Sergi Ferrete": {
+    "photo": [9]
+  },
+  "Marcin Czerniawski": {
+    "photo": [10]
+  },
+  "Thomas Lipke": {
+    "photo": [11]
   },
   "Pixabay": {
-    "photo": [2, 3, 9, 11, 13, 14, 15]
-  },
-  "Unknown": {
-    "photo": [5, 6, 8, 10, 12, 16, 17, 18, 19]
+    "photo": [1, 8, 12]
   }
 }