diff --git a/core/models.py b/core/models.py
index 44d8a62e..2c6a6f5a 100644
--- a/core/models.py
+++ b/core/models.py
@@ -12,6 +12,8 @@ from django.contrib.staticfiles.storage import staticfiles_storage
 from django.utils.html import escape
 from django.utils.functional import cached_property
 
+import os
+
 from phonenumber_field.modelfields import PhoneNumberField
 
 from datetime import datetime, timedelta, date
@@ -664,10 +666,10 @@ class SithFile(models.Model):
             if self.is_folder:
                 for c in self.children.all():
                     c.move_to(self)
-                shutil.rmtree(settings.MEDIA_ROOT + old_file_name)
+                shutil.rmtree(os.path.join(settings.MEDIA_ROOT, old_file_name))
             else:
                 self.file.save(name=self.name, content=self.file)
-                os.remove(settings.MEDIA_ROOT + old_file_name)
+                os.remove(os.path.join(settings.MEDIA_ROOT, old_file_name))
 
     def __getattribute__(self, attr):
         if attr == "is_file":
diff --git a/core/views/files.py b/core/views/files.py
index 0d4179bb..f8a49f27 100644
--- a/core/views/files.py
+++ b/core/views/files.py
@@ -38,10 +38,11 @@ def send_file(request, file_id, file_class=SithFile, file_attr="file"):
             ):
         raise PermissionDenied
     name = f.__getattribute__(file_attr).name
-    with open((settings.MEDIA_ROOT + name).encode('utf-8'), 'rb') as filename:
+    filepath = os.path.join(settings.MEDIA_ROOT, name)
+    with open(filepath.encode('utf-8'), 'rb') as filename:
         wrapper = FileWrapper(filename)
         response = HttpResponse(wrapper, content_type=f.mime_type)
-        response['Content-Length'] = os.path.getsize((settings.MEDIA_ROOT + name).encode('utf-8'))
+        response['Content-Length'] = os.path.getsize(filepath.encode('utf-8'))
         response['Content-Disposition'] = ('inline; filename="%s"' % f.name).encode('utf-8')
         return response
 
diff --git a/sas/models.py b/sas/models.py
index 2abcce9f..b12adeb0 100644
--- a/sas/models.py
+++ b/sas/models.py
@@ -7,6 +7,7 @@ from django.core.files.base import ContentFile
 
 from PIL import Image
 from io import BytesIO
+import os
 
 from core.models import SithFile, User
 from core.utils import resize_image, exif_auto_rotate
@@ -17,7 +18,7 @@ class Picture(SithFile):
 
     @property
     def is_vertical(self):
-        with open((settings.MEDIA_ROOT + self.file.name).encode('utf-8'), 'rb') as f:
+        with open(os.path.join(settings.MEDIA_ROOT, self.file.name).encode('utf-8'), 'rb') as f:
             im = Image.open(BytesIO(f.read()))
             (w, h) = im.size
             return (w / h) < 1
@@ -67,7 +68,7 @@ class Picture(SithFile):
     def rotate(self, degree):
         for attr in ['file', 'compressed', 'thumbnail']:
             name = self.__getattribute__(attr).name
-            with open((settings.MEDIA_ROOT + name).encode('utf-8'), 'r+b') as file:
+            with open(os.path.join(settings.MEDIA_ROOT, name).encode('utf-8'), 'r+b') as file:
                 if file:
                     im = Image.open(BytesIO(file.read()))
                     file.seek(0)
diff --git a/sas/templates/sas/picture.jinja b/sas/templates/sas/picture.jinja
index 0f091966..68253ea4 100644
--- a/sas/templates/sas/picture.jinja
+++ b/sas/templates/sas/picture.jinja
@@ -21,11 +21,12 @@
 }
 </style>
 
-<link rel="prefetch" href="{{ url("sas:picture", picture_id=picture.get_previous().id} }}"> <!-- Firefox -->
-<link rel="prerender" href="{{ url("sas:picture", picture_id=picture.get_previous().id }}"> <!-- Chrome -->
-
-<link rel="prefetch" href="{{ url("sas:picture", picture_id=picture.get_next().id} }}"> <!-- Firefox -->
-<link rel="prerender" href="{{ url("sas:picture", picture_id=picture.get_next().id }}"> <!-- Chrome -->
+{% if picture.get_previous() %}
+<link rel="preload" as="image" href="{{ url("sas:download_compressed", picture_id=picture.get_previous().id) }}">
+{% endif %}
+{% if picture.get_next() %}
+<link rel="preload" as="image" href="{{ url("sas:download_compressed", picture_id=picture.get_next().id) }}">
+{% endif %}
 
 {% endblock %}