You can attach an image within a comment. The picture below is with using shortcuts. But you can do it by adding a comment as well. It does not put the picture inline within the text. But it is attached to the ticket. 

Currently, you can not add the image inline with the text. There are a lot of ideas around attaching images in our idea exchange: https://community.incidentiq.com/search?q=image&content_type%5B0%5D=ideation