Does the appearance of images and fantasies of people while remembering Allah, and the accompanying whispers of Shirk (polytheism), affect the soundness of faith? And is that considered Shirk, even if the heart is believing and abhors Shirk, or is it merely an obsessive-compulsive whisper that requires special treatment?

A piece of advice for the one afflicted with waswas (obsessive whispering): seek total refuge from waswas, do not yield to Satan, and know that your fear of disbelief is evidence of your adherence to the religion. You should occupy your time with learning, righteous deeds, acts of obedience, dhikr (remembrance of Allah), and seeking forgiveness. Also, frequently seek refuge from shirk (definition) (associating partners with Allah) by saying: "O Allah, I seek refuge in You from associating partners with You knowingly, and I seek Your forgiveness for what I do not know."