I know this is a frequently requested feature from many users. Not sure why Strava hasn't rolled this out as a option under Preferences | ☑️ Show Elapsed Time in All Activity
I regularly post photos with workout stats on Facebook and the exhausting steps I take to getting the Elapsed Time stats onto the images: Edit Activity | change Type of Activity from None to Race | Save | share Photos to my Gmail and repeat. Once I'm done, return to Edit Activity | change Type of Activity from Race to None | Save.
I prefer to show the total time it has taken me to complete my Trail Run, Ride or Swim.