When I am creating a new Confluence template, I'll often first create a page in Confluence that represents roughly what I want to see in the template. I then copy/paste this into a template page and code up with Instructional text, page properties and the like. This works fine - unless the copied content has an image.

In that case, when I paste into a template it appears to display fine, but when saved, it either doesn't save those changes OR sometimes seems to delete/forget the whole template!

Reproduction steps

1. Create a new Confluence document that includes one or more embedded image (in my case I've also had these within an Expand macro - not sure if that's important)
2. In a Space, create a new Template
3. Select all the content in the original document you created (in edit mode)
4. Paste it into the template
5. Save the template
6. Verify the template either doesn't save or is completely lost

Workaround

While creating a template, Use 'Insert Files and Images' > 'Search on other pages' to find the original image from the corresponding page and Insert it.