You can choose to enable or disable the download option for every gallery in Picflow at any time. Simply go to the gallery settings and configure it.
They will also see a download button on the top right of each image page. Here they will have the option to choose what size they want to download.
This will download all of the original files that you uploaded in a ZIP file.
You can specify which sizes you'd like to provide. Picflow will automatically resize the to the available dimensions.
Note: Images sizes currently work only for individual images