What possible evidence have you seen to suggest that your employer is monitoring/intercepting text and picture messages on your personal phone?
If you're only asking because you think they might be, and have no evidence to support it, then you might want to check out the tinfoilhat.com forums.
If you're only asking because you think they might be, and have no evidence to support it, then you might want to check out the tinfoilhat.com forums.