I found this very clear image of the Woodrow Wilson High School ROTC photo, and that short pudgy guy in the middle is definitely James Bookhout. The face is a very good match to Bookhout's SMU photos, and it is a very good match to the Ruby impostor photo.
Do you see the round face on both? Round face. Round face. Round face. Round face.
Short with a round face. That is him, James Bookhout. That is not Jack Ruby. His face wasn't like that.