Water marks are special icons that are seen when you open a folder which is full of pictures or videos or music files .These icons can be seen on the lower right corner of the window
For example, if you open the MY Music folder in windows, you will be able to see music like water mark icon on the lower right corner of the window.
This is to indicate that the folder has a lot of musical content.
If you do not want any of such kind of watermark icon you can disable tham in windows .
Right click My Computer and click properties and go to the advanced tab and then click settings under Performance. Now just scroll down the list until you see
” Use a background image for each folder type” and then uncheck it and click the apply button.