Watermark reloaded plugin is an addon for Bp _gallery. It allows you to watermark the images uploaded via bp-galler.
This plugin is an extension of Watermark reloaded plugin, and needs watermark reloaded plugin to be installed to function. You can set the font,color,text,size etc using the settings of water mark reloaded plugin for WordPress.
Once this plugin is active, any image uploaded via bp-gallery will be automatically watermarked.
Here is a screenshot.