diff --git a/src/py/webui/upload.py b/src/py/webui/upload.py
index 20b4fb2..8a3a246 100644
--- a/src/py/webui/upload.py
+++ b/src/py/webui/upload.py
@@ -63,3 +63,4 @@ def upload_photo(section: str):
         return {"status": "ok", "uploaded": uploaded}
 
     return {"error": "No valid files uploaded"}, 400
+
diff --git a/src/py/webui/webui.py b/src/py/webui/webui.py
index b40b126..ae1c554 100644
--- a/src/py/webui/webui.py
+++ b/src/py/webui/webui.py
@@ -136,6 +136,10 @@ def photos(section, filename):
     """Serve uploaded photos from disk."""
     return send_from_directory(PHOTOS_DIR / section, filename)
 
+@app.route("/photos/<path:filename>")
+def serve_photo(filename):
+    photos_dir = Path(__file__).resolve().parents[3] / "config" / "photos"
+    return send_from_directory(photos_dir, filename)
 
 @app.route("/site-info")
 def site_info():
@@ -154,6 +158,28 @@ def update_site_info():
         yaml.safe_dump(data, f, sort_keys=False, allow_unicode=True)
     return jsonify({"status": "ok"})
 
+@app.route("/api/themes")
+def list_themes():
+    themes_dir = Path(__file__).resolve().parents[3] / "config" / "themes"
+    themes = [d.name for d in themes_dir.iterdir() if d.is_dir()]
+    return jsonify(themes)
+
+
+@app.route("/api/thumbnail/upload", methods=["POST"])
+def upload_thumbnail():
+    PHOTOS_DIR = app.config["PHOTOS_DIR"]
+    file = request.files.get("file")
+    if not file:
+        return {"error": "No file provided"}, 400
+    filename = "thumbnail.png"
+    file.save(PHOTOS_DIR / filename)
+    # Update site.yaml
+    with open(SITE_YAML, "r") as f:
+        data = yaml.safe_load(f)
+    data.setdefault("social", {})["thumbnail"] = filename
+    with open(SITE_YAML, "w") as f:
+        yaml.safe_dump(data, f, sort_keys=False, allow_unicode=True)
+    return jsonify({"status": "ok", "filename": filename})
 
 # --- Run server ---
 if __name__ == "__main__":
diff --git a/src/webui/js/site-info.js b/src/webui/js/site-info.js
index 3ce842c..7e4e9b5 100644
--- a/src/webui/js/site-info.js
+++ b/src/webui/js/site-info.js
@@ -63,6 +63,58 @@ document.addEventListener("DOMContentLoaded", () => {
   const convertImagesCheckbox = document.getElementById("convert-images-checkbox");
   const resizeImagesCheckbox = document.getElementById("resize-images-checkbox");
 
+  // --- Theme select ---
+  const themeSelect = document.getElementById("theme-select");
+
+  // --- Thumbnail upload ---
+  const thumbnailInput = form?.elements["social.thumbnail"];
+  const thumbnailUpload = document.getElementById("thumbnail-upload");
+  const thumbnailPreview = document.getElementById("thumbnail-preview");
+
+  if (thumbnailUpload) {
+    thumbnailUpload.addEventListener("change", async (e) => {
+      const file = e.target.files[0];
+      if (!file) return;
+      const formData = new FormData();
+      formData.append("file", file);
+      const res = await fetch("/api/thumbnail/upload", { method: "POST", body: formData });
+      const result = await res.json();
+      if (result.status === "ok") {
+        if (thumbnailInput) thumbnailInput.value = result.filename;
+        if (thumbnailPreview) {
+          thumbnailPreview.src = `/photos/${result.filename}`;
+          thumbnailPreview.style.display = "block";
+        }
+        status.textContent = "✅ Thumbnail uploaded!";
+        setTimeout(() => status.textContent = "", 2000);
+      } else {
+        status.textContent = "❌ Error uploading thumbnail";
+        setTimeout(() => status.textContent = "", 2000);
+      }
+    });
+  }
+
+  // Fetch theme list and populate select
+  if (themeSelect) {
+    fetch("/api/themes")
+      .then(res => res.json())
+      .then(themes => {
+        themeSelect.innerHTML = "";
+        themes.forEach(theme => {
+          const option = document.createElement("option");
+          option.value = theme;
+          option.textContent = theme;
+          themeSelect.appendChild(option);
+        });
+        // Set selected value after loading config
+        fetch("/api/site-info")
+          .then(res => res.json())
+          .then(data => {
+            themeSelect.value = data.build?.theme || "";
+          });
+      });
+  }
+
   // Load config
   if (form) {
     fetch("/api/site-info")
@@ -81,10 +133,16 @@ document.addEventListener("DOMContentLoaded", () => {
         form.elements["info.keywords"].value = Array.isArray(data.info?.keywords) ? data.info.keywords.join(", ") : (data.info?.keywords || "");
         form.elements["info.author"].value = data.info?.author || "";
         form.elements["social.instagram_url"].value = data.social?.instagram_url || "";
-        form.elements["social.thumbnail"].value = data.social?.thumbnail || "";
+        if (thumbnailInput) thumbnailInput.value = data.social?.thumbnail || "";
+        if (thumbnailPreview && data.social?.thumbnail) {
+          thumbnailPreview.src = `/photos/${data.social.thumbnail}`;
+          thumbnailPreview.style.display = "block";
+        }
         form.elements["footer.copyright"].value = data.footer?.copyright || "";
         form.elements["footer.legal_label"].value = data.footer?.legal_label || "";
-        form.elements["build.theme"].value = data.build?.theme || "";
+        if (themeSelect) {
+          themeSelect.value = data.build?.theme || "";
+        }
         form.elements["legals.hoster_name"].value = data.legals?.hoster_name || "";
         form.elements["legals.hoster_adress"].value = data.legals?.hoster_adress || "";
         form.elements["legals.hoster_contact"].value = data.legals?.hoster_contact || "";
@@ -149,9 +207,9 @@ document.addEventListener("DOMContentLoaded", () => {
       updateMenuItemsFromInputs();
       updateIpParagraphsFromInputs();
 
-      // --- Build object with checkboxes ---
+      // --- Build object with checkboxes and theme select ---
       const build = {
-        theme: form.elements["build.theme"].value,
+        theme: themeSelect ? themeSelect.value : "",
         convert_images: !!(convertImagesCheckbox && convertImagesCheckbox.checked),
         resize_images: !!(resizeImagesCheckbox && resizeImagesCheckbox.checked)
       };
@@ -167,7 +225,7 @@ document.addEventListener("DOMContentLoaded", () => {
         },
         social: {
           instagram_url: form.elements["social.instagram_url"].value,
-          thumbnail: form.elements["social.thumbnail"].value
+          thumbnail: thumbnailInput ? thumbnailInput.value : ""
         },
         menu: {
           items: menuItems
diff --git a/src/webui/site-info/index.html b/src/webui/site-info/index.html
index 58ecae2..e8ad676 100644
--- a/src/webui/site-info/index.html
+++ b/src/webui/site-info/index.html
@@ -55,8 +55,10 @@
       <fieldset>
         <legend>Social</legend>
         <label>Instagram URL: <input type="text" name="social.instagram_url"></label><br>
-        <label>Thumbnail: <input type="text" name="social.thumbnail"></label><br>
-      </fieldset>
+        <label>Thumbnail: <input type="text" name="social.thumbnail" readonly></label>
+        <input type="file" id="thumbnail-upload" accept="image/png,image/jpeg,image/webp">
+        <img id="thumbnail-preview" src="" alt="Thumbnail preview" style="max-width:100px;display:none;">
+        </fieldset>
       <fieldset>
         <legend>Menu</legend>
         <div id="menu-items-list"></div>
@@ -69,7 +71,9 @@
       </fieldset>
       <fieldset>
         <legend>Build</legend>
-        <label>Theme: <input type="text" name="build.theme"></label><br>
+        <label>Theme:
+            <select name="build.theme" id="theme-select"></select>
+        </label>
         <label>
             <input type="checkbox" name="build.convert_images" id="convert-images-checkbox">
             Convert images