To ensure that the library data set is not updated by other jobs while the IEBIMAGE job is running, DISP=OLD should be specified on the SYSUT1 DD statement.

SYSUT1 DD may specify a user image library. This library must have the same characteristics as SYS1.IMAGELIB, and can subsequently be identified to the system with the SETPRT macro instruction, or renamed "SYS1.IMAGELIB". If you are using JES, you cannot specify a user image library with SETPRT.