I really love my OP Black Apricot case: https://oneplus.net/oneplus-x-black-apricot-case
But right now, using this Spigen from Amazon: http://www.amazon.com/OnePlus-Spigen%C2%AE-Resilient-Ultimate-protection/dp/B017UILJB8/
(I'm super biased, I've bought a Spigen case for almost every phone that I've owned. They look good and are quite protective. Can't beat a 2-year warranty.)
Yeah I'm jealous of my brothers OPX's. The screen is beautiful. I know you don't use themes on your OPO but since you'll loose the dark amoled oos theme on the opx you should use this.
https://play.google.com/store/apps/details?id=com.pippo96.oxygenred
Use arcus to unpack it and get the amoled themes https://play.google.com/store/apps/details?id=pixkart.arcus
This might be useful for you. I don't think you can change the size within the camera app.
https://play.google.com/store/apps/details?id=com.paul.xicon
You could also look at other camera apps that might give you the option.
Yes and no. I use the app FolderSync to monitor changes in folder /storage/sdcard0/DCIM and to move any files created to /storage/sdcard1/DCIM.
You also have a sync option to force media scan so gallery apps immediately know the photos are in the new folder.