How to remove old Android images/packages/apps? The initial setup on my Android device was using 4gb of space. After several upgrades it's using 7.5gb and most of that is Android OS crap. Personal files and non-Google apps are on an SD card. I need to clean up internal storage. This is the equivalent of finding an old Linux image in synaptic and then remove completely.
Is there a tool similar to synaptic for Android?
Synaptic is a GUI tool over apt package manager that manages .deb packages built for  Linux distros. Android's package management is inside a Java environment, totally different from Linux distros. Android's Java apps are built as .apk (zip) files and are managed by PackageManager which may also be used from commandline tool pm.

What you are looking for i.e. the purging of old packages is not simply achievable on Android. You can uninstall user apps and their data will also be deleted from /data/app/&lt;PKG-NAME&gt;, /data/data/&lt;PKG-NAME&gt; and /sdcard/Android/data/&lt;PKG-NAME&gt;. You can delete any left over files from /sdcard yourself.  

But there are a number of packages (system apps) that are part of Android core framework and they store their data on different directories under /data which also include your preferences, settings, databases, backups, contacts, messages, caches, logs etc. You can't remove them all because - unlike Linux - everything on Android isn't neceassarily a part of some package.

So what you can do easily is Factory Reset. It'll bring your device to clean state by removing almost everything from /data partition. However it will remove your settings, personal data &amp; all user installed apps. So keep a backup before doing so.

If you don't want to start from zero, you need to analyze space usage manually, not possible without root access or at least custom recovery. If you have rooted your device, you can use a  GUI app like SDMaid to check space usage of /data (and even other format-able) partitions in detail. Or simply use du command from recovery or from terminal emulator within Android. See this for a practical example of space usage.