I would also like to chime in on this topic.
My application is that I want to create a time lapse video from hand-held photographs. Specifically, I want to show how various plants in my garden are growing over the spring - especially hops which grow rapidly up a steel cable.
To do this I need to align each photo so they are at least roughly showing the same perspective. Affinity photo do this very well and shows the images as a stack of layers within the Photo persona.
I can then export each individual layer, by switching on each layer individually and going file > export. Each image is the right size, and I can import into Premiere to make a video.
But this is already quite time consuming - and eventually I hope to have hundreds of images per time lapse. This will be a project lasting several months!
If I go to the Export persona, I can have each layer as a slice, and I can export all the slices at once, in multiple formats. And each one will be not quite right, not quite the right size, and will result in a much more jerky time lapse than individual exporting.
Photoshop suffers from exactly the same issue.
I am not very skilled in either Affinity Photo or Photoshop, but I would have thought that being to export multiple layers with the same canvas size simultaneously would be a fairly common need, and also easily developed? Especially given the comments of UI designers on this thread.
