What is the ruling on unintentional imaginations—such as the image of a shin when reading: "The Day a shin will be uncovered and they will be invited to prostration but not be able"—and does the ruling differ if one doubts whether they were intentional?

Reflecting upon the Day of Resurrection, Paradise, and Hell is a virtuous act that removes heedlessness from hearts. Contemplating the meanings of Allah's attributes, without delving into their modality, rectifies the heart. However, reflecting on the modality of His attributes leads to perdition. The Ahl al-Sunnah (definition) (Sunni Muslims) believe in affirming the attributes as they are mentioned in the texts, while declaring Allah free from resemblance to creation and acknowledging the inability of intellects to comprehend their modality. And whatever comes to mind regarding this, Allah is far removed from it, for Allah the Almighty says: "There is nothing like unto Him" (Quran 42:11), and "Do you know of any similitude to Him?" (Quran 19:65), and "And there is none comparable to Him" (Quran 112:4), and "And they do not encompass Him in knowledge" (Quran 20:110). If this belief is firmly established, then obsessive thoughts (waswas) will not harm, and if they occur, seek refuge with Allah from Satan and strive against yourself. Know that Allah has forgiven the whisperings of the soul as long as they are not acted upon or spoken. Turn away from these obsessive thoughts, for you will be rewarded for striving against them.