If you want to protect your intellectual properties, say, don't want your client to be able to directly download your images until getting paid, you can disable downloading images for any gallery. This option is enabled by default.
To disable downloading manually, go to the gallery you want to disable downloading for. Then click on the 'gear' button to switch to the 'Gallery Settings' tab, you can then toggle the 'Downloadable' item to 'Off', and it's done!
On the viewer's side, they can not right click the image to save to a computer, nor long-push an image on a phone, to save to a photo album.
Simply toggle the 'Downloadable' switch to 'On' on your gallery setting form(under the 'gear' button tab).
Yes! PDF/ZIP download and 'Downloadable' does not interfere with each other, they are separate features DpiApp provides. Even if your client can download a PDF of the gallery images, he still can't directly download each image on the web page.
Sort of. Unless they're tech geeks or programmers, it is relatively hard for normal people to find a way around to download your images. But if they take a photo of their monitor or screenshot their phone, DpiApp can't do anything to prevent it.