This happens with images sized bigger than 2048px. After all a phone is not a workstation
So if I downside to less than 2048px it will be OK? Lol - yes I know the iphone is a small engine, but zooming like that isn't a problem on any other iOS photo apps. Thanks again for your help, that's been really useful.
Richard, it's the price to pay for big image sizes in combination with multiple layers. And, as far as I know, the other apps do not have layers ... memory is really tight on these devices.
I think you're right. I works OK with smaller size images and few images. Thanks.