Revert "Remove unsafe operations"
Revert "Remove unsafe operations"

This reverts commit 3564b66c66d593206f59229bc2a8a35d898b3b32.

nwin/rust-image,PistonDevelopers/image,hetzge/image,dtwood/piston-image,lady-segfault/image,twoodford/image,bvssvni/image,mbrubeck/image,tomaka/image,theotherphil/image,TyOverby/rust-image,PistonDevelopers/image,JaySon-Huang/image,huonw/image