Allow images in upload signer

functions/upload.ts

@@ -1,12 +1,17 @@
 import { AwsClient } from "aws4fetch";
 
 const contentTypes: { [k: string]: string } = {
+  avif: "image/avif",
   gif: "image/gif",
+  jpeg: "image/jpeg",
+  jpg: "image/jpeg",
   m4v: "video/x-m4v",
   mkv: "video/x-matroska",
   mov: "video/mp4",
   mp4: "video/mp4",
+  png: "image/png",
   webm: "video/webm",
+  webp: "image/webp",
   wmv: "video/x-ms-wmv",
 };