if your service is open source I can try to fork it and give one similar to altcoinstalks
The source code is not the point of talkimg. To run the website you money to buy the infrastructure to host all those images, this is main point of a website like that.
Take a look here, this basically the same website as talkimg. There are others if you research more...
https://imgbb.com/He used some already existing scripts for image sharing.