What is the ruling on publishing pictures of a veiled female writer on social media for the purpose of marketing her works and interacting with her audience, taking into consideration that the pictures are official and document events such as book signings and press interviews?

It is permissible to publish the picture if it does not show what is unlawful for men to see; otherwise, it is not. The preponderant opinion is that a woman's face is 'awrah (private, to be covered) and must be covered.

It is better to suffice with writing a biography on the cover without including personal photos. There is no harm in gaining fame.