Get rid of shadow maps for images

Fixed the image bitmap creation to use the End of the object section
instead of using the map size. This means that the bitmap covers at
most one word of bits past the end of the object section.

Reverts shadow map logic introduced by multi image CL:
(commit dcdc85bb)

Bug: 26317072
Change-Id: I181cf3490a5b292c00c6b0f97536f3206adcd091