KB32016: How to create an image watermark in Report Services Documents.

A watermark is a faint design appearing in the background of every page of the document. Watermarks in documents can be either text or an image. Image watermarks typically identify or decorate pages as following.
 

ACTION: 
See below for the steps to create an image wartermark:
 

1. Open a document in Design view in Desktop and select the "Document Properties" from the "Format" menu.

• Click Format button.
• Select the Image watermark radio button and specify an image source. Note that the image is automatically resized to fit within the document margins by default. Users can scale the image manually by selecting a percentage from the Scale drop-down list.

 
Note: Any object that has a fill color, including a white fill, covers the watermark. If users want a watermark to show through a Grid/Graph, set the background of the Grid/Graph’s cells to "transparent". Similarly, the background of a text field, rectangle, and so on must be transparent to allow the watermark to show as shown.

• Click OK to save it.