I wrote the js code to change the image

static/script/wallpaperLoad.js

@@ -0,0 +1,37 @@
+function load(date) {
+    fetch(`https://api.starlio.space/wallpaper/${date}`).then(res => {
+        res.json().then(data => {
+            console.log(data);
+            if (data.length === 0) return;
+
+            document.querySelector("div.wallpaper img").src = data.url;
+            document.querySelector("div.wallpaper div.wallpaper-text div.wallpaper-desc h1").innerHTML = data.title;
+            document.querySelector(".copyright").innerHTML = `Image Credit & Copyright: ${data.copyright}`;
+            document.querySelector(".desc").innerHTML = data.explanation;
+        });
+    });
+}
+
+function parseURL() {
+    const pathname = document.location.pathname
+
+    if (isNaN(new Date(pathname).getTime())) return null;
+    if (!isValidDate(pathname)) return null;
+
+    return Number(pathname);
+}
+
+
+/* THX, bro <3
+ https://stackoverflow.com/a/35413963/20781634
+ */
+function isValidDate(dateString) {
+  var regEx = /^\d{4}-\d{2}-\d{2}$/;
+  if(!dateString.match(regEx)) return false;
+  var d = new Date(dateString);
+  var dNum = d.getTime();
+  if(!dNum && dNum !== 0) return false;
+  return d.toISOString().slice(0,10) === dateString;
+}
+
+load(parseURL());