This might happen if you are using ExtendSim 10.0.7. The application development framework used by ExtendSim had a bug in their software that could cause pictures/images on model worksheets to disappear. They have fixed the bug and future releases of ExtendSim will use the corrected version of their software.

Unfortunately, there is no workaround for this in 10.0.7. To obtain an alpha (pre-release) version of ExtendSim that corrects this issue, contact ExtendSim Support if you need help with this.