TOPIC: Image is Not Showing in QGIS plugin informtn pane

I created a QGIS plugin with Plugin Builder. Even though the icon set in the metadata.txt is displayed in the Plugin Manager list (left to the plugin name in the installed plugin list), it is not showing in the plugin information pane (the right pane where the details of the plugin is displayed on selecting the plugin). Instead of the supplied icon, a blue question mark is shown at the top right of the information pane.

I tried installing many plugins from the QGIS repository and for none of them the correct icon is displayed. But for the core plugins (those implemented as plugin DLL) is displaying the icon correctly.

Is there anything specific to be done to have the icon displayed in the top right corner of the plugin manager information pane?