Create some marketing materials

plugin logo	A plugin logo that is a 72x72px PNG/JPG/GIF image. Atlassian strongly recommends a chiclet-style background for the logo (check out this free Photoshop template). This format works best with upcoming changes to the user interfaces of UPM and the Atlassian Marketplace.
plugin icon	The plugin icon that is a 16x16px PNG/JPG/GIF pixel version of your plugin logo or an appropriate derivation of it.
banner	Currently, UPM 2.0 does not display banners but later versions will. Moreover, a banner is required by the Atlassian Marketplace. So, since ArfX's functionality (nothing really) is likely to work in future versions of both JIRA and UPM, this example adds a banner to show up when the software supports it.  Here is how to add it to your plugin Plugin Metadata Files used by UPM and Marketplace