While researching this webcam cache that I have missed out on getting during a prior trip to San Antonio in 2012, I noticed someones post that showed the webcam in the window.
I did some side research and discovered that your "helper" can go to this link (visit link) and get a live view of the webcam that does not take a picture like it used to.
This will allow your helper to grab a screenshot of you standing in front of the Alamo via the webcam as this cache is intended.
The cache listing could be changed to note this new information.
P.S. Beware of advertisements that sometimes pop up on the video without warning...