Dynamic Report Title and Images

I would like to set the logo and title in the header of the report based on

a) Parameter values
Title field in the report properties

I have a master page and on this master page I have dynamic text for the title and image that references an url that is built using the parameter passed.

However, neither of them seem to work

What is the best/right way of
a) replacing images / text in the Master page based on parameter values/ properties.

Thanks