Hey girlie! It HAS been a while! I've had to greatly limit my time spent writing and reading about my boys due to school and a busy life in general (senior year kills, man, and it's only the 3rd week haha), so I don't get on very much.
As for your question, if you post your chapters through your phone, I have no clue how to add pictures or gifs. I've never tried it from there.
However, posting them on a computer is pretty easy. On the side, as you write or edit your chapter, there is the OPTIONS box, right? So under the word 'options', choose 'Advanced' instead of 'Basic'. Then at the bottom of the box, you can add youtube videos and pictures/gifs. Warning: you copy and paste links, so if you have a saved picture that you're wanting to put in there, you either have to upload it to some internet site or find a new one. Hope it works for you! If you do use your phone or ipod to update, I can see if I can find out how to do it there :) Good luck!