foxwells.vinboard: fix standalone image links

src/modules/foxwells.js

@@ -190,7 +190,9 @@ async function findSuitableImage(msg) {
   } else {
     for (const embed of msg.embeds) {
       if (!embed.url) continue;
-      if (embed.image) {
+      if (embed.url && /(jpe?g|png|gif|webp)$/.test(url)) {
+        out.url = embed.url;
+      } else if (embed.image) {
         out.url = embed.image.url;
         break;
       } else if (embed.video) {