Download original files

Hello @Jim Fryer 

You are right that Lightroom Mobile (and the cloud-oriented Lightroom desktop app) upload originals to cloud storage.  The apps *might* retain some original images in the local app cache, but only as long as there is plenty of free space on the device.  When device storage gets low, the app will purge original images to free up device storage.

If it's important for you to keep originals on the device (ie., you want to be able to zoom in to see the finest details that may not be so clear with Lightroom's 2560-pixel proxy images), here's what I recommend: 

- place images in an album, and then viewing the list of all albums, tap the 3-dots button to the right of your album's name, and then select Store Locally.  This will download original files to your device, and will keep them there even if the app does housekeeping to purge other cached files. 

If I've been traveling, and want to keep the originals on the device to be able to edit them while on planes/trains, I will import the images, and place them in an album that's set to Store Locally.  When I'm back home and I'm confident all my recent imports and edits are fully synced, then I might later disable Store Locally for that specific album.  Again, this all depends on how much free space I have on my device.  My current phone has less overall storage than my previous device, and so I notice I use Store Locally less often.

Your Lightroom 1 TB plan does provide access to the Lightroom desktop app, in which you can specify to keep originals synced to your computer in app settings.  If you had a mobile only plan, and were interested in quickly obtaining all your originals at once for safekeeping on a computer/backup drive, then I would recommend you try the Lightroom Downloader app for Windows or Mac OS.  More info on that here: https://helpx.adobe.com/lightroom-cc/kb/download-lightroom-photos.html 

I hope some bit of info here is useful to you!