Following is the smugmug RF license agreement:

License For Commercial Use
What you can do: Photographer grants you a perpetual, non-exclusive, non-transferable, worldwide license to use this image for permitted commercial purposes, defined as:

advertising, promotion, brochures, packaging
as part of a commercial website for promotional purposes (maximum 800x600pixels) use
prints, posters, flyers, tearsheets for promotional purposes (not for resale)
prints, posters, or other commercial display of image
magazines, books, newspapers, other printed publications
video, broadcast, theatrical
What you may not do: Buyer may not resell, relicense, redistribute without express written permission from photographer. Use as a derivative work, and reselling or redistributing such derivative work is prohibited. Images may not be used in a pornographic, obscene, illegal, immoral, libelous or defamatory manner. Images may not be incorporated into trademarks, logos, or service marks. Image may not be made available for download.

Photographer retains all rights, license, copyright, title and ownership of the image(s).

There is no warranty, express or implied, with the purchase of this digital image file. Neither photographer nor SmugMug will be liable for any claims, or incidental, consequential or other damages arising out of this license or buyer's use of the image(s).

* In short, for a one time fee you may use the image commercially for almost any purpose, anywhere, as many times as you wish.
But, unless stated otherwise, note that all RF images are provided without model or property releases. It is your responsibility to either obtain a release when required or to make sure the type of use you make of the image does not require a release.