Welcome to the forum
It all depends on how much knowledge you have about photography before making comments about other peoples pictures.
To actually talk or write on the subject even a basic knowledge on rule of thirds-composition -lighting- editing and everything else concerning photography is a must.
Without that your talk is worthless let alone writing on the subject. Yes you can get the information from books and the like but they are other peoples thoughts and opinions not yours which is what you are trying to get across.
Even then talking/writing about other peoples photos is a bit of a liberty in my opinion unless the person who took the photos gives their permission.
Realspeed