what does the facebook mobile icon mean?

[N]

if someone is on facebook and your on the computer it, now on the computer it tells if their on their mobile by showing a "mobile" in green, or just the mobile picture, or mobile and something like 15m. does the mobile picture mean that they or on their mobile right now? or could it just mean that their phone is on and that their facebook is connected without them actually being on the app?

[Jonathan]

It means that the person has disconnected from facebook "15 minutes" ago .

[Daniel]

it Means They Are Signed into Facebook On there Mobile Phone The 15 M means They Were Last Active 15 minutes Ago