For versioning : Add the following stanza to app.conf to add your app into the app launcher. Fill out each attribute as described.
[launcher]
author=<author of app>
description=<textual description of app>
version=<version of app>
For logos : Place app icon images at the following location:
$SPLUNK_HOME/etc/apps//static/
with files name using followin rules (appIcon.png,appIcon_2x.png, appLogo.png...) : http://docs.splunk.com/Documentation/Splunk/6.2.5/AdvancedDev/AddConfigurations
The Link from hgrow is exactly what you are looking for. Everything you need is explained there.