When doing some searches to check if anyone else called the image of 'a male/female couple on a bench with him holding another man's hand behind her back' the "bisexual bench", it looks like online magazine Queerty made a poor choice almost ten years ago:

Is It Time To Start Being Nicer To Bisexuals?

(Tweeted on 20th July 2016. Original still at https://twitter.com/Queerty/status/755751402371223552 at time of writing.)

It did not go well and virtually of the comments are calling them out on the use of the stereotypical image:

"Replace 'Bisexuals' with 'Gays' or 'Transgenders' (sic) and see if it's an appropriate headline. Disgusting."

"oh groan on the 3some image.!!"

"wow this is hateful and horrible delete this immediately!!"

"A good starting point is to include bi people's voices & not use stereotypical pics. More tips here"

etc.

Interestingly, the most popular response I've spotted was a quoted retweet posted nine months later:

It's time to stop using pictures implying bisexuals are cheaters .

(Tweeted on 21st April 2017, retweeted over fifteen thousand times. Original deleted, but at on archive sites.)