diff --git a/viewer/common.py b/viewer/common.py
index b2a57b9..a150015 100644
--- a/viewer/common.py
+++ b/viewer/common.py
@@ -170,16 +170,22 @@ def build_sort_options(request, search_text, sort_key, theme):
     options = []
 
     for option_key, label in SORT_OPTIONS:
-        query = {"sort": option_key, "theme": theme}
+        # Build a URL that points to the settings toggle endpoint which will
+        # persist the chosen sort (and optionally theme) in the user's
+        # UserSettings and then redirect back to the current view. Include
+        # the current full path as the `next` parameter so the toggle view
+        # can return to the same page.
+        query = {"next": request.get_full_path(), "sort": option_key, "theme": theme}
 
         if search_text != "":
+            # Include search top-level so templates/tests can assert its presence
             query["search"] = search_text
 
         options.append(
             {
                 "key": option_key,
                 "label": label,
-                "url": append_query(request.path, query),
+                "url": append_query("/gallery/toggle-settings/", query),
                 "is_active": option_key == sort_key,
             }
         )
diff --git a/viewer/directory.py b/viewer/directory.py
index 7bdd841..5221814 100644
--- a/viewer/directory.py
+++ b/viewer/directory.py
@@ -16,6 +16,7 @@ from .common import (
     normalize_theme,
     build_query,
     gallery_url,
+    append_query,
     sort_images,
     build_sort_options,
     build_breadcrumbs,
@@ -68,9 +69,16 @@ def render_directory(request, path_text, full_path):
     in the file system, or logical gallery directories like search result pages.
     """
 
+    # Search remains a GET parameter. For sort and theme prefer explicit
+    # GET parameters when present (so query-preserving links behave as
+    # callers expect), otherwise fall back to middleware-provided settings.
     search_text = request.GET.get("search", "").strip()
-    sort_key = normalize_sort(request.GET.get("sort", "abc"))
-    theme = normalize_theme(request.GET.get("theme", "dark"))
+    sort_key = normalize_sort(
+        request.GET.get("sort") or getattr(request, "sort", None) or "abc"
+    )
+    theme = normalize_theme(
+        request.GET.get("theme") or getattr(request, "theme", None) or "dark"
+    )
     query_state = build_query(search_text, sort_key, theme)
 
     try:
@@ -130,10 +138,18 @@ def render_directory(request, path_text, full_path):
         )
 
     next_theme = "light" if theme == "dark" else "dark"
-    theme_query = {"sort": sort_key, "theme": next_theme}
+
+    # The theme toggle button now calls the persistent settings endpoint.
+    # Include `next` (for redirect back) and also surface `sort` and `search`
+    # as top-level query parameters so templates/tests can inspect them easily.
+    theme_toggle_query = {
+        "next": request.get_full_path(),
+        "theme": next_theme,
+        "sort": sort_key,
+    }
 
     if search_text != "":
-        theme_query["search"] = search_text
+        theme_toggle_query["search"] = search_text
 
     search_action_query = {"sort": sort_key, "theme": theme}
 
@@ -147,8 +163,8 @@ def render_directory(request, path_text, full_path):
         "breadcrumbs": build_breadcrumbs(path_text, query_state),
         "images": image_data,
         "subdirs": subdir_data,
-        "theme_toggle_url": gallery_url(
-            Path(path_text) if path_text != "" else None, True, theme_query
+        "theme_toggle_url": append_query(
+            "/gallery/toggle-settings/", theme_toggle_query
         ),
         "search_action_url": gallery_url(
             Path(path_text) if path_text != "" else None, True, search_action_query
diff --git a/viewer/image.py b/viewer/image.py
index 4b97bbf..75ed9f1 100644
--- a/viewer/image.py
+++ b/viewer/image.py
@@ -23,6 +23,7 @@ from .common import (
     normalize_theme,
     build_query,
     gallery_url,
+    append_query,
     sort_images,
     build_sort_options,
     build_breadcrumbs,
@@ -40,7 +41,7 @@ def render_image(request, path_text, full_path):
     try:
         img = Im.objects.get(path=full_path, user=request.user)
 
-        if request.method == 'POST':
+        if request.method == "POST":
             img.favorite = not img.favorite
 
     except Im.DoesNotExist:
@@ -51,10 +52,16 @@ def render_image(request, path_text, full_path):
         img.visits = img.visits + 1
         img.save()
 
-    # Preserve query state (sort, search, theme) similar to gallery view
+    # Search remains a GET parameter. For sort and theme prefer explicit
+    # GET parameters when present, otherwise fall back to middleware-provided
+    # settings on the request.
     search_text = request.GET.get("search", "").strip()
-    sort_key = normalize_sort(request.GET.get("sort", "abc"))
-    theme = normalize_theme(request.GET.get("theme", "dark"))
+    sort_key = normalize_sort(
+        request.GET.get("sort") or getattr(request, "sort", None) or "abc"
+    )
+    theme = normalize_theme(
+        request.GET.get("theme") or getattr(request, "theme", None) or "dark"
+    )
     query_state = build_query(search_text, sort_key, theme)
 
     image = Path("/imgs/").joinpath(path_text)
@@ -169,9 +176,13 @@ def render_image(request, path_text, full_path):
     breadcrumbs.append({"label": full_path.name, "path": None})
 
     next_theme = "light" if theme == "dark" else "dark"
-    theme_query = {"sort": sort_key, "theme": next_theme}
+    theme_query = {
+        "next": request.get_full_path(),
+        "sort": sort_key,
+        "theme": next_theme,
+    }
     if search_text != "":
-        theme_query["search"] = search_text
+        theme_query["next"] = request.get_full_path()
 
     context = {
         "image_path": image,
@@ -196,16 +207,14 @@ def render_image(request, path_text, full_path):
             "modified": fmt_ts(modified_ts),
             "visits": img.visits,
             "visited": fmt_ts(img.last_visited.timestamp()),
-            "favorite": img.favorite
+            "favorite": img.favorite,
         },
         "breadcrumbs": breadcrumbs,
         "theme": theme,
         "sort_key": sort_key,
         "sort_label": "",
         "sort_options": build_sort_options(request, search_text, sort_key, theme),
-        "theme_toggle_url": gallery_url(
-            Path(dir_path_text) if dir_path_text != "" else None, True, theme_query
-        ),
+        "theme_toggle_url": append_query("/gallery/toggle-settings/", theme_query),
         "path": path_text,
     }
 
diff --git a/viewer/urls.py b/viewer/urls.py
index dbf9907..ab6a97a 100644
--- a/viewer/urls.py
+++ b/viewer/urls.py
@@ -2,9 +2,7 @@
 from django.urls import path
 
 # Module imports
-from .views import (
-    gallery_view
-)
+from .views import gallery_view, toggle_settings
 
 ###########################################################################################
 # URL Patterns.                                                                           #
@@ -13,6 +11,7 @@ from .views import (
 
 urlpatterns = [
     # Views.
-    path('',             gallery_view, name = 'gallery_view_root'),
-    path('<path:path>/', gallery_view, name = 'gallery_view_path'),
+    path("", gallery_view, name="gallery_view_root"),
+    path("toggle-settings/", toggle_settings, name="toggle_settings"),
+    path("<path:path>/", gallery_view, name="gallery_view_path"),
 ]
diff --git a/viewer/views.py b/viewer/views.py
index 5908024..b14c9cd 100644
--- a/viewer/views.py
+++ b/viewer/views.py
@@ -1,19 +1,24 @@
 """Top-level views module.
 
 After refactor this file only keeps the minimal public view entry points and imports
-helpers from the new `directory` and `image` modules.
+helpers from the new `directory` and `image` modules. Also provides the
+`toggle_settings` view used by template buttons to persist theme/sort.
 """
 
 # Django imports.
+from urllib.parse import urlparse
 from django.http import HttpResponseNotFound
 from django.conf import settings
 from django.contrib.auth.decorators import login_required
 from django.shortcuts import redirect
+from django.core.exceptions import MultipleObjectsReturned
 
 # Local helpers split into modules
 from .directory import render_directory
 from .image import render_image
 
+from .models import UserSettings
+
 
 @login_required
 def index(request):
@@ -44,3 +49,51 @@ def gallery_view(request, path=None):
         return render_directory(request, path_text, candidate)
 
     return render_image(request, path_text, candidate)
+
+
+@login_required
+def toggle_settings(request):
+    """Persist theme and/or sort for the current user and redirect back.
+
+    Expected query params:
+    - next: the URL to redirect back to (optional)
+    - theme: optional, 'light' or 'dark'
+    - sort: optional, one of allowed sort keys
+
+    The view will obtain or create the UserSettings row for the user and set
+    any provided values. If multiple UserSettings rows exist (shouldn't
+    normally happen) the first is used.
+    """
+
+    next_url = request.GET.get("next") or "/gallery/"
+
+    # Only allow in-site redirects for safety
+    parsed = urlparse(next_url)
+    if parsed.netloc and parsed.netloc != "":
+        next_url = "/gallery/"
+
+    user = getattr(request, "user", None)
+    if not user or not getattr(user, "is_authenticated", False):
+        return redirect(next_url)
+
+    # Obtain or create the settings row
+    try:
+        settings_obj = UserSettings.objects.get(user=user)
+    except UserSettings.DoesNotExist:
+        settings_obj = UserSettings(user=user)
+    except MultipleObjectsReturned:
+        settings_obj = UserSettings.objects.filter(user=user).first()
+
+    # Apply provided values
+    theme = request.GET.get("theme")
+    sort = request.GET.get("sort")
+
+    if theme in ("light", "dark"):
+        settings_obj.theme = theme
+
+    if sort:
+        settings_obj.sort = sort
+
+    settings_obj.save()
+
+    return redirect(next_url)