Extracting App Version in Android

Check the timeline of your phone and filter for apk's.

All the major vendors provide Timeline in their apps, so far I used with great success Cellebrite, Oxygen Forensics, Compelson and Belkasoft products for this. I don't know what your options are, but I bet that other forensic softwares generate timeline as well.

If you are a geek, look at the logs manually ) for example grep is my friend, faster then all the above mentioned options )

I am examining image of my phone, I want to know what was the version of an app that was installed at that time. Can I know this ? If yes then how?

There are many tools available that can do this. One easy to use relatively recent tool is Java based and will run on any platform.

https://github.com/google/android-classyshark/releases/download/8.1/ClassyShark.jar

Just run it as java -jar ClassyShark.jar

Open the ".apk" of the app you're interested in and select "AndroidManifest.xml".

Odds are the version information will be there.