You always have to look for the presence of an SD card or media
directory.
Now, from here, I have no idea what to tell you.
I don't know where that data will be stored.
You have to keyword search.
Every application does things slightly different.
You will see that some of them go to the Android directory.
Some create their own directory.
Every app could be different.
Different application versions could be different.
So if you just keyword search for your app of interest--
for example, Facebook-- it should tell you exactly where
all of these files exist.