How does Eric P. Kelly use imagery in The Trumpeter of Krakow?

Imagery:

"But, still holding to the trumpet, the youth fell back against the supporting wall and blew one last glorious note; it began strongly, trembled, and then ceased - broken like the young life that gave it birth - and at that moment those below applied the torch to the wooden church, and it, too, rose in flames to Heaven, with the soul of the youth among them."

"Clad in fiery garments which smelled of fire and brimstone and which seemed to blaze and burn and give off a greenish smoke and flame, he moved slowly forward, waving in his right hand a scepter of flaming red which was crackling with heat as a green bough crackles when it burns, while from its end little balls of fire were dripping."