Yariv,
In the spirit of clarification, I wanted to let you know that TestStand user interface controls aren't ActiveX controls. They are special controls that are meant to communicate with the TestStand Manager controls in order to perform operations and be updated.
The TestStand user interface controls do not support displaying an image and therefore can not be a picture button. If you need a picture button in your application you can use one of the regular CVI user interface buttons. Based on the button's behavior, you can call the TestStand engine through ActiveX or use one of the Manager control references to perform the operation you are looking for.
Regards,
Santiago D