Images in Templates
Due to some technical and usability hurdles, images are currently not supported yet, but it is something we are exploring.
The reasons are generally the same reasons as attachments.
When inserting a template, we take the body of the response template, resolve any variables in it, and then insert it into the Jira issue. Any images that would be used in a template would have to be uploaded to the Jira issue before it can be referenced in the template.
This is where things get a bit more tricky: Atlassian doesn't provide any way for addon vendors like us to store any files within your Jira instance. There is no shared storage, or anything like that. We can only attach files to issues. Thus, we would have to store your image somewhere in our infrastructure. From there, we would then insert some kind of marker in a template saying use IMAGE_X here wherever the image should be referenced. From there, when inserting a template, we would need upload the image to the Jira issue first to obtain the unique id and URL to the file. Then, we can replace the marker with the real values and insert the template.
Of course, uploading the file to Jira first introduces delays, as the rest of the template cannot move forward until the file is uploaded, which depending on file size, and how many images referenced in a template, this could take a while.
Additionally, we generally want to avoid storing customer files in our infrastructure due to privacy reasons, on top of potential storage costs and bandwidth consumption for uploads.
We are in the process of exploring ways around these limitations, and hope to have a viable solution in the near future.