Originally Posted by Ko.Fe.
From my experience monitor calibration is only necessary half of the in home printing with matching screen colors process.
For regular person bw image posting on internet it is next to irrelevant. Because image is to be ruined by Apple screen on mobile device many NA viewers are using
For this most common scenario I recommend to check your internet shared images from another devices. Like someone else computer. If it looks recognizable, nothing to worry about.
That's really bad advice. You should always start with the best image you can produce. Sorry to step on toes but this philosophy is why there are so many terrible looking images posted. If you calibrated then you know your image looks great to the people that care and calibrate their monitor. You can't second guess what someone else's monitor looks like.