Source: https://www.spigotmc.org/resources/fredashays-item-frame-protect.54574/
We use this plugin as a second layer of protection ontop of World Edit to keep our Image’s on Map item frames safe.
This plugin protects item frames and their contents.
To install this plugin, copy the plugin JAR file to your server’s plugins folder.
The plugin is fairly simple; it forbids one player from destroying another player’s item frames, or placing an item in another player’s item frames, or removing an item from another player’s item frames. An OP must be wielding an OP stick to destroy or place or remove an item from another player’s item frame.