Use website instead of $_SERVER['SERVER_NAME'] to identify external images (#156)
Use website instead of $_SERVER['SERVER_NAME'] to identify external images (#156)

(cherry picked from commit f4991e4e50897b201536485082e2cda95f123d49)

bramley/phplist3,mariez/phplist3,samtuke/phplist3,bramley/phplist3,samtuke/phplist3,mariez/phplist3,samtuke/phplist3,bramley/phplist3,mariez/phplist3,phpList/phplist3,phpList/phplist3,samtuke/phplist3,mariez/phplist3,mariez/phplist3,phpList/phplist3,phpList/phplist3,phpList/phplist3,bramley/phplist3,samtuke/phplist3,bramley/phplist3