mailman: larger signup screenshots

mail/mailman/create_account.markdown

@@ -7,32 +7,32 @@ Given that mailing lists may be public and used by external users, the service i
 
 2. Enter your account info. If you have a D-PHYS account, we recommend to use `username@phys.ethz.ch` as e-mail address, and your D-PHYS login as username. The password should ideally be separate, and can be reset in case you forgot it.
 
-[[!img /media/mail/mailman/signup_1.png size="450x"]]
+[[!img /media/mail/mailman/signup_1.png size="550x"]]
 
 3. The service will send you a message to the entered email address, in order to make sure you are the owner of that email, as it will grant you ownership to the linked mailing list subscriptions.
 
-[[!img /media/mail/mailman/signup_2.png size="450x"]]
+[[!img /media/mail/mailman/signup_2.png size="550x"]]
 
 4. Click on the verification link you received by mail and press the button to confirm the email.
 
-[[!img /media/mail/mailman/signup_3.png size="450x"]]
+[[!img /media/mail/mailman/signup_3.png size="550x"]]
 
 5. Next you can sign in with your mailing list account and username.
 
-[[!img /media/mail/mailman/signup_4.png size="450x"]]
+[[!img /media/mail/mailman/signup_4.png size="550x"]]
 
 6. Open the account preferences.
 
-[[!img /media/mail/mailman/signup_5.png size="450x"]]
+[[!img /media/mail/mailman/signup_5.png size="550x"]]
 
 7. Enter your name and time zone.
 
-[[!img /media/mail/mailman/signup_6.png size="450x"]]
+[[!img /media/mail/mailman/signup_6.png size="550x"]]
 
 8. You may optionally link additional emails to your mailman account. This is useful if you also want to send messages using any of your email aliases.
 
-[[!img /media/mail/mailman/signup_7.png size="450x"]]
+[[!img /media/mail/mailman/signup_7.png size="550x"]]
 
 9. Only one of your email addresses can be marked as primary, but the choice does not really matter.
 
-[[!img /media/mail/mailman/signup_8.png size="450x"]]
+[[!img /media/mail/mailman/signup_8.png size="550x"]]