Usually when showing off a project it makes sense to show it working correctly. The first photo shows that the software doesn't work consistently which could give someone a bad first impression. It's not like the photo is in a section that is about its limitation, but in a section introducing the project.
If your face detection works 80% or 95% of the time, don't try and deceive me into thinking it's 100% accurate, only to leave me disappointed when I go through the effort of downloading/configuring/testing it and then find out it's worse that the solution I'm trying to replace.
