Taking file uploader as background for Canvas

So I need help once again. I’ve not really used Canvas and the documentation didn’t provided me help on my problem.

What I want to do is to build a simple Story/Status/Snap system like Instagram, Whatsapp or Snapchat for my writing community. For that, I wanted to allow users to upload their images and add text on them. Then other users can see them. I could have just added a label on Image and make it display the content of textbox and then download the pdf but unfortunately image source won’t allow pdf so users can’t watch each other’s stories. I know Canvas is the way to go but how can I do it? Also, if there is another solution, I’m all open