Press g+g on your keyboard and select priorities. Click edit at the priority you'd like to give a new icon. Click select after the Icon URL:
Screen Shot 2016-12-26 at 16.27.06.png
If you have access to the images url (<your JIRA>/images/icons/priorities/) you could add your icons there. If you don't, you could refer to an http:// url as you can see from the description with the image path if you can.
Connect with like-minded Atlassian users at free events near you!Find a group
Connect with like-minded Atlassian users at free events near you!
Unfortunately there are no AUG chapters near you at the moment.Start an AUG