How can I hang a picture on my wallboard bathroom wall?

Scotch does make hanging strips that hold quite a bit of weight, but I see where you’d be nervous about a mirror. There are also monkey hooks (I believe that’s what they’re called) and they do go into the wall, but the hole is tiny and they hold a lot more weight. Good luck!

Some of the command strips can hold heavy items. Just check the packaging for the weight limits. Good luck.

There are special screws . Ask your local hardware

Not sure where you want a mirror, or what size, but you can always find a joist in the ceiling next to the wall. With a bit of ingenuity, you can add a hook and fix a decorative chain to the mirror. If it isn't in the center, you could use a molly bolt in the center of the ceiling where it meets the wall. To keep the mirror from swinging, out from the wall at the bottom, a bit of double stick tape or a command strip would work.

You could put molly bolts and hooks in the ceiling to suspend it in front of the wall. I'd put some cork pieces on the back of the mirror frame so it doesn't bang into the wall.

Command adhesive strips will work just make sure to use quite a bit of them so that it will be sufficient to hold up.

Thanks everyone. I’ll try the adhesive strips!

I'm not sure if the adhesive strips will work in the long haul. It might if there's no shower in the room, but with humidity, the adhesive will degrade eventually. There are really pretty slim standing mirrors. That might be safer.

How To Hang A Mirror Over Bathroom Panels

https://www.dbsbathrooms.co.uk/news/how-to-hang-a-mirror-over-bathroom-panels/