Hi,
I usually browse voyager and like to share some funny memes.
I'm used to browsing inside Firefox through wefwef.app there to share I long press an image and click Share as an image.
on PWA I d'ont have share as an image in that menu.
I tried the share button but it just download an image on the phone instead of opening my app of choice with the img.
I'm on android
I'm using the PWA on android (with Vivaldi browser) and I just long-press the image and get the share image option... so, I don't know why it doesn't work for you.
That's odd. Both options open the share menu for me and then paste the image right into the app I've chosen to share with (say WhatsApp)... so, yeah, seems to be a Firefox thing indeed.