diff --git a/frontend/elements/photo-lightbox.html b/frontend/elements/photo-lightbox.html
index 7e1f238..6d7ca9e 100644
--- a/frontend/elements/photo-lightbox.html
+++ b/frontend/elements/photo-lightbox.html
@@ -242,7 +242,7 @@ Polymer({
     console.log("Download tapped");
 
     var anchor = document.createElement('a');
-    anchor.href = this.base + this.item.path + "/" + this.item.filename;
+    anchor.href = this.base + this.item.path + this.item.filename;
     anchor.setAttribute("download", this.src.replace(/.*\/([^/]+)$/, "$1"));
     anchor.style.display = "none";
     document.body.appendChild(anchor);
@@ -355,10 +355,15 @@ Polymer({
   attached: function() {
     var base = document.querySelector("base");
     if (base) {
-        this.base = new URL(base.href).pathname.replace(/\/$/, ""); /* Remove trailing slash if there */
+        base = new URL(base.href).pathname.replace(/\/$/, ""); /* Remove trailing slash if there */
     } else {
-        this.base = "";
+        base = "";
     }
+    /* If base is configured, add a trailing slash */
+    if (base.length) {
+      base += "/";
+    }
+    this.base = base;
   }
 });
 </script>