MikeR wrote:What do you think about the idea of using a grab (and grabbing) cursor to show it ?
I don't generally agree, for two reasons: 1) There is already a zoom in/out cursor displaying by default, which insinuates to the user that they can click to zoom in/out of the photo. 2) Swipe is not a functional navigation method from mouse/trackpads on desktop devices, when the alternative is to simply use keyboard-arrows or mouse-click. Click-drag-release is tedious.
We won't be adding this as default, but you could change it by custom CSS. It would require a few extra lines though if you want to change between the "grab" and "grabbing" cursors when the visitors actually clicks down ...