With regard to the images that are prominent and visible, such as those that are on the covers -- for example -- it is not permissible to bring them into the mosque, because the angels do not enter a house in which there are images. If the angels are offended by the smell of onions and leeks, then they will be offended by these images which keep them out – i.e., prevent the angels from entering the mosque. But if the images are hidden and are not sought in and of themselves, then I hope that there will be nothing wrong with that, because they are hidden inside the book and also they are not the purpose for which the book is brought. If a person thinks that he can do what is better and more perfect, and can erase the faces, then the problem is resolved. End quote. 

And Allaah knows best. 

Shaykh Muhammad ibn Saalih al-‘Uthaymeen (may Allaah have mercy on him)