I develop games and I have used Poser / Daz 2D images for those, mostly Poser. We convert them to the lowest resolution needed to improve the game performance. These games run fast (30 - 60 frames per second i.e. it is cycling through the code 30 - 60 times a second and displaying images to screen at that speed). The minute you start using high resolution images you limit your game to only run on desktop or the latest and greatest mobile devices (which are scarce outside of first world markets.) My games in Unity that is rendering 3D real time will only run on fairly recent devices, it stutters on older phones. That's pretty much  the reason all apps reduce the resolution.

For simply transferring your renders from your PC to your mobile, you can use cloud storage that links them, Bluetooth or USB. The resolution will remain the same. You do not specifically need an app for that.

Where I would like to see an app or progress is to have a Poser light that you can run on a mobile with a draft render, and then pay a  fee to upload and render these on a server i.e. Bondware's server for the final quality render and then the render is returned to you (In fact I'd pay for this even from a PC, because a high quality render uses up 100% of my PC resources and then takes a few hours.) I think this would open up the software to 1000s of people that only use mobile internet and do not own laptops or desktops. 

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