Just updating an app to work on the new iPadPro and found that my @2x images are too large on the screen as compaited to iPad Air etc. Is there something else I must do ?
@2x appears too big on ipad pro 10.5 inch
Did you also insert the image as @1x ?
When I'm in doubt, I copy in @1x, @2x, @3x !
All recent iPad models (9.7", 10.5" and 12.9") all use @2x images and the screens are all at 264dpi. Thus the images will all be the exact same physical size. The original iPads (pre-Retina) are all at 132dpi and use @1x. The minis have the same resolution as 9.7 inch models and will either use @1x or @2x. The dpi will be higher on those, so artwork will be physically smaller.
Are you doing any custom drawing? In my app, I get identical-sized images everywhere on 9.7, 10.5 and 12.9 iPads.
Another question... how are you comparing the output? Are you looking at simulator screenshots? If so, there seem to be some bugs in Xcode 9 regarding screenshots of 9.7 iPads (captured size ended up being 1268x1691 for some reason instead of the proper 1536x2048). But if you're looking at physical devices, they should all be identically sized.
Side note: Strongly consider using vector-based images. Back in OS X 10.4 (Tiger) there were plans on having true resolution-independence (to include non-integral scale factors). At that time, I authored all my artwork in Adobe Illustrator and output as PDF. These days, I can now leverage that same artwork under iOS which uses much simpler integral scale factors. And Xcode (at least with version 8.x and 9.x) can work with PDF. Under the covers, Xcode will generate all necessary rasterized images for you. Saves a huge amount of time. Xcode 9 also allows you to embed the original vector data too (useful for at least tab bar artwork to provide some super-sized accessibility content).