I installed this after installing (and then disabling) Scissors Continued.
Scissors Continued also gave me the "The plugin generated 192 characters . . ." warning as well. Im using the Roots theme which endvors to make all links root relative.
The plugin generated 192 characters of unexpected output during activation. If you notice “headers already sent” messages, problems with syndication feeds or other issues, try deactivating or removing this plugin.
Notice: Undefined variable: metadata in /Applications/MAMP/htdocs/tr_wordpress/wp-content/plugins/scissors-watermark/scissors-and-watermark.php on line 1115