There are several applications where only "Picture Files" are allowed to use.
Greenshot is great to capture a image to Clipboard. But additional steps are necessary to incorporate the capture to those application via save to a file and drag & drop this file.
A fantastic feature could be a fake "Drag & Drop" where captured image is automatic saved to a temporary file and is signalled on Drop Message at target app.
I would very much second this feature, this would be great when working with github issues where you have to save the file before dragging and I assume the same is necessary in Jira