In Adventure Mode, paintings can still be broken by the player, although this could be because paintings are considered entities.
This could be a problem for certain maps which have hidden tunnels behind paintings.
ย
Related issues
Comments
Hi there!
This looks like a duplicate ofย MC-579, which works as intended.
You could use the command
/data modify entity <uuid> Invulnerable set value 1b
, replace the <uuid> with the UUID of the item frame/painting (should automatically fill when you delete the placeholder), and then it should not be breakable in Adventure Mode anymore.
You can suggest a change to this feature at https://feedback.minecraft.net/hc/en-us.

Ok thanks!
Thank you for your report!
We're tracking this issue as MC-579, so this ticket is being resolved and linked as a duplicate.
That ticket has already been resolved as working as intended, which means this is not considered a bug and won't be fixed. Please do not leave a comment on the linked ticket.
If you haven't already, you might like to make use of the search feature to see if the issue has already been mentioned.
Quick Links:
๐ Issue Guidelines โ ๐ฌ Community Support โ ๐ง Mojang Support โ โ๏ธ Feedback and Suggestions โ ๐ Game Wiki