On this page you can preselect the photos you may want to have. In the end you can choose "Save selection". You can do this for all photo sets on the site. 
 
You can then choose "Select sizes", to go to a page with an overview of your selection, where you can refine your selection and choose the sizes etc. of your photos. 
 
In the end you can choose "Order photos" to go to a page where you can enter your address details. 
 

Select
all Un-select
all Save
selection Select
sizes