840a7572_ices___Open_Static_Map_Service__Description
[Request Parameter] bestfit [Example Request Data] 40.063175,-76.734664,39.960338,-76.306892 [Required] Yes, if the center parameter is not present and no POIs are present Note: bestfit will override center [Description] 
If a center point is not desired, a bounding box can be used to specify the area of the map to be shown. This parameter takes a latitude/longitude pair as an upper left corner bound and one for the lower right. It then creates a map based on those bounds given.
MapQuest Platform Web Services : Open Static Map Service
Description