What reasons were given by Islamic doctrine for the exclusion of icons?

History
 What reasons were given for the acceptance of icons by the Christian church?
What reasons were given by Islamic doctrine for the exclusion of icons? In what instances do Christians forbid the use of images?
In what context(s) does Islam allow for the use of figural images (humans and/animals)?
“Iconoclasm in Islamic Art” by Sarah Ruthven
“The Icon Controversy – Christian History Made Easy”