Is it permissible for me to be an ad publisher on my website, knowing that ads containing pictures of women, or ads for Islamic websites, or for websites free of unlawful content, may appear?

There is no harm in creating a website for publishing advertisements if it adheres to Sharia controls, such that it does not contain images of women, nor musical instruments, nor promote forbidden things (like alcohol and pork), nor usurious banking transactions, nor corrupt tourist sites, nor suspicious matters. For a Muslim is entrusted with the morals, wealth, and honor of Muslims, and his mindfulness of Allah in his advertisements is a preservation of the trust. Aiding in the dissemination of the unlawful is a waste and betrayal of the trust, in accordance with His, the Almighty's, saying: (O YOU WHO HAVE BELIEVED, DO NOT BETRAY ALLAH AND THE MESSENGER OR BETRAY YOUR TRUSTS WHILE YOU KNOW).