diff --git a/konova/static/images/error_imgs/croc_technician_400_sm.png b/konova/static/images/error_imgs/croc_technician_400_sm.png
new file mode 100644
index 00000000..20da9cc6
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diff --git a/konova/static/images/error_imgs/croc_technician_500_sm.png b/konova/static/images/error_imgs/croc_technician_500_sm.png
new file mode 100644
index 00000000..0ec19d86
Binary files /dev/null and b/konova/static/images/error_imgs/croc_technician_500_sm.png differ
diff --git a/konova/utils/mailer.py b/konova/utils/mailer.py
index bdb60614..ce6db5e2 100644
--- a/konova/utils/mailer.py
+++ b/konova/utils/mailer.py
@@ -5,7 +5,7 @@ Contact: michel.peltriaux@sgdnord.rlp.de
 Created on: 09.11.20
 
 """
-from django.core.mail import send_mail
+from django.core.mail import send_mail, EmailMultiAlternatives
 from django.template.loader import render_to_string
 from django.utils.translation import gettext_lazy as _
 
@@ -45,6 +45,19 @@ class Mailer:
             auth_password=self.auth_password
         )
 
+    def send_via_bcc(self, recipient_list: list, subject: str, msg: str):
+        """
+        Sends a mail with subject and message where recipients will be masked via bcc
+        """
+        email_obj = EmailMultiAlternatives(
+            subject,
+            msg,
+            self.from_mail,
+            bcc=recipient_list,
+        )
+        email_obj.attach_alternative(msg, "text/html")
+        return email_obj.send(fail_silently=self.fail_silently)
+
     def send_mail_shared_access_removed(self, obj, user, municipals_names):
         """ Send a mail if user has no access to the object anymore
 
@@ -115,7 +128,7 @@ class Mailer:
         }
         msg = render_to_string("email/sharing/shared_access_given_team.html", context)
         user_mail_address = users_to_notify.values_list("email", flat=True)
-        self.send(
+        self.send_via_bcc(
             user_mail_address,
             _("{} - Shared access given").format(obj.identifier),
             msg
@@ -141,7 +154,7 @@ class Mailer:
         }
         msg = render_to_string("email/sharing/shared_access_removed_team.html", context)
         user_mail_address = users_to_notify.values_list("email", flat=True)
-        self.send(
+        self.send_via_bcc(
             user_mail_address,
             _("{} - Shared access removed").format(obj.identifier),
             msg
@@ -167,7 +180,7 @@ class Mailer:
         }
         msg = render_to_string("email/recording/shared_data_unrecorded_team.html", context)
         user_mail_address = users_to_notify.values_list("email", flat=True)
-        self.send(
+        self.send_via_bcc(
             user_mail_address,
             _("{} - Shared data unrecorded").format(obj.identifier),
             msg
@@ -193,7 +206,7 @@ class Mailer:
         }
         msg = render_to_string("email/recording/shared_data_recorded_team.html", context)
         user_mail_address = users_to_notify.values_list("email", flat=True)
-        self.send(
+        self.send_via_bcc(
             user_mail_address,
             _("{} - Shared data recorded").format(obj.identifier),
             msg
@@ -219,7 +232,7 @@ class Mailer:
         }
         msg = render_to_string("email/checking/shared_data_checked_team.html", context)
         user_mail_address = users_to_notify.values_list("email", flat=True)
-        self.send(
+        self.send_via_bcc(
             user_mail_address,
             _("{} - Shared data checked").format(obj.identifier),
             msg
@@ -244,7 +257,7 @@ class Mailer:
         }
         msg = render_to_string("email/other/deduction_changed_team.html", context)
         user_mail_address = users_to_notify.values_list("email", flat=True)
-        self.send(
+        self.send_via_bcc(
             user_mail_address,
             _("{} - Deduction changed").format(obj.identifier),
             msg
@@ -270,7 +283,7 @@ class Mailer:
         }
         msg = render_to_string("email/deleting/shared_data_deleted_team.html", context)
         user_mail_address = users_to_notify.values_list("email", flat=True)
-        self.send(
+        self.send_via_bcc(
             user_mail_address,
             _("{} - Shared data deleted").format(obj.identifier),
             msg
diff --git a/templates/400.html b/templates/400.html
index 58e29443..5c9f5c19 100644
--- a/templates/400.html
+++ b/templates/400.html
@@ -5,7 +5,7 @@
     <div class="jumbotron">
         <div class="row">
             <div class="col-auto">
-                <img src="{% static 'images/error_imgs/croc_technician_400.png' %}" style="max-width: 150px">
+                <img src="{% static 'images/error_imgs/croc_technician_400_sm.png' %}" style="max-width: 150px">
             </div>
             <div class="col-sm-12 col-md-9 col-lg-9 col-xl-10">
                 <h1 class="display-4">{% fa5_icon 'question-circle' %}400</h1>
diff --git a/templates/500.html b/templates/500.html
index b53b072f..e5e9fee2 100644
--- a/templates/500.html
+++ b/templates/500.html
@@ -5,7 +5,7 @@
     <div class="jumbotron">
         <div class="row">
             <div class="col-auto">
-                <img src="{% static 'images/error_imgs/croc_technician_500.png' %}" style="max-width: 150px">
+                <img src="{% static 'images/error_imgs/croc_technician_500_sm.png' %}" style="max-width: 150px">
             </div>
             <div class="col-sm-12 col-md-9 col-lg-9 col-xl-10">
                 <h1 class="display-4">{% fa5_icon 'fire-alt' %} 500</h1>