Is it permissible to allow advertising on my website if there are symbolic female images or female images in signatures, even though the advertising banner itself is free of female images and is religiously permissible?

It is not permissible to accept the publication of advertisements featuring images of girls on your website, as this constitutes cooperation in sin. Allah Almighty says: "And cooperate in righteousness and piety, but do not cooperate in sin and aggression. And fear Allah; indeed, Allah is severe in penalty." (Al-Ma'idah: 2).