Summary

Image attachment is deleted from the Jira issue view if the image was initially copied (using Ctrl+C or Cmd+C or Right-Click+Copy) from a text field (multi-line type such as description) and pasted into another text field (multi-line type such as environment). This happens when the initial image is deleted from the source field (from where the image was copied).

Environment

Jira Cloud instance.

Diagnosis

To replicate the issue, you can follow the below steps:

• Goto any Text Field (multi-line) type Field on your issue, like the Description field, and add an image on this field.
• Right Click on this image and select "Copy" to copy this image. Or You can use Ctrl+C or Cmd+C to copy the image along with some other Data/Texts. 
• Goto another Text Field (multi-line) type Field on the same issue, and paste the Image+Texts from your Clipboard.
• You will see in the Attachments section that still there is only 1 image, although the image is present in two fields.
• Now delete the Image from the Source Text Field (multi-line) type Field.
• You will see the Image gets deleted from the Attachments section.
• The Image will show "Preview Unavailable" on the Second field where you had copy-pasted the Image with texts. 

Cause

• When we Copy an image\attachment using Ctrl+C or Cmd+C or Right-Click+Copy, then we basically perform a soft copy so we don’t duplicate the same attachment twice on the issue. Thus, the copied image that we see in the second field, is just a soft link to the Image that is already present in the Source field. 
• So if you delete the image\attachment from the Source field, it also gets deleted from the Attachments section and the Image also gets removed from the Second field or becomes useless as it shows an "Unavailable" error. 

Solution

• Whenever you have a requirement to copy Data from a Text Field (multi-line) type Field on your issue and paste it into another Text Field (multi-line) type Field, then you should not Ctrl+C or Cmd+C or Right-Click+Copy to copy the image.
• Instead, Copy the data/Texts separately first and paste them in the second field.
• Then Go back to the Source Field, right-click on the Image and select the option "Copy Image" instead of "Copy".
• After this, if you will paste it in the second field, the Image will get uploaded as a Duplicate Attachment in the Attachments section of the Issue.
• Now if you delete the data+Image from the Source Field, then the Original Image will get deleted from the Attachments section of the Issue but the Duplicate Image will continue to exist in the Attachments section and the Image will continue to be visible on the Second field, where it was pasted.
• Video for reference:
   copy-image.mp4