diff --git a/data/web/inc/functions.customize.inc.php b/data/web/inc/functions.customize.inc.php
index 0da8c356..b7292357 100644
--- a/data/web/inc/functions.customize.inc.php
+++ b/data/web/inc/functions.customize.inc.php
@@ -2,6 +2,7 @@
 function customize($_action, $_item, $_data = null) {
 	global $redis;
 	global $lang;
+  global $LOGO_LIMITS;
   
   switch ($_action) {
     case 'add':
@@ -35,6 +36,23 @@ function customize($_action, $_item, $_data = null) {
                 );
                 return false;
               }
+              if ($_data[$_item]['size'] > $LOGO_LIMITS['max_size']) {
+                $_SESSION['return'][] = array(
+                  'type' => 'danger',
+                  'log' => array(__FUNCTION__, $_action, $_item, $_data),
+                  'msg' => 'img_size_exceeded'
+                );
+                return false;
+              }
+              list($width, $height) = getimagesize($_data[$_item]['tmp_name']);
+              if ($width > $LOGO_LIMITS['max_width'] || $height > $LOGO_LIMITS['max_height']) {
+                $_SESSION['return'][] = array(
+                  'type' => 'danger',
+                  'log' => array(__FUNCTION__, $_action, $_item, $_data),
+                  'msg' => 'img_dimensions_exceeded'
+                );
+                return false;
+              }
               $image = new Imagick($_data[$_item]['tmp_name']);
               if ($image->valid() !== true) {
                 $_SESSION['return'][] = array(
diff --git a/data/web/inc/vars.inc.php b/data/web/inc/vars.inc.php
index 5578dfd3..afc801e4 100644
--- a/data/web/inc/vars.inc.php
+++ b/data/web/inc/vars.inc.php
@@ -126,6 +126,15 @@ $MAILCOW_APPS = array(
   )
 );
 
+// Logo max file size in bytes
+$LOGO_LIMITS['max_size'] = 15 * 1024 * 1024; // 15MB
+
+// Logo max width in pixels
+$LOGO_LIMITS['max_width'] = 1920;
+
+// Logo max height in pixels
+$LOGO_LIMITS['max_height'] = 1920;
+
 // Rows until pagination begins
 $PAGINATION_SIZE = 25;
 
diff --git a/data/web/lang/lang.de-de.json b/data/web/lang/lang.de-de.json
index 3efd5afa..ddadfac6 100644
--- a/data/web/lang/lang.de-de.json
+++ b/data/web/lang/lang.de-de.json
@@ -394,7 +394,9 @@
         "goto_invalid": "Ziel-Adresse %s ist ungültig",
         "ham_learn_error": "Ham Lernfehler: %s",
         "imagick_exception": "Fataler Bildverarbeitungsfehler",
+        "img_dimensions_exceeded": "Grafik überschreitet die maximale Bildgröße",
         "img_invalid": "Grafik konnte nicht validiert werden",
+        "img_size_exceeded": "Grafik überschreitet die maximale Dateigröße",
         "img_tmp_missing": "Grafik konnte nicht validiert werden: Erstellung temporärer Datei fehlgeschlagen.",
         "invalid_bcc_map_type": "Ungültiger BCC-Map-Typ",
         "invalid_destination": "Ziel-Format \"%s\" ist ungültig",
diff --git a/data/web/lang/lang.en-gb.json b/data/web/lang/lang.en-gb.json
index 58ad6665..ec97d0ae 100644
--- a/data/web/lang/lang.en-gb.json
+++ b/data/web/lang/lang.en-gb.json
@@ -394,7 +394,9 @@
         "goto_invalid": "Goto address %s is invalid",
         "ham_learn_error": "Ham learn error: %s",
         "imagick_exception": "Error: Imagick exception while reading image",
+        "img_dimensions_exceeded": "Image exceeds the maximum image size",
         "img_invalid": "Cannot validate image file",
+        "img_size_exceeded": "Image exceeds the maximum file size",
         "img_tmp_missing": "Cannot validate image file: Temporary file not found",
         "invalid_bcc_map_type": "Invalid BCC map type",
         "invalid_destination": "Destination format \"%s\" is invalid",