Savageduck
On 2014-09-20 03:51:46 +0000, nospam <nospam@nospam.invalid>said:

nospam
In article <s0qp1adosbs2srb293smuem1f5cnml763b@4ax.com>, Eric Stevens <eric.stevens@sum.co.nz>wrote:

Eric Stevens
So what happens when you want a high quality TIFF of the same size as the original file? Do you expand by resampling your low-res highly compressed JPG?

nospam
questions like this mean you don't understand how it works.

it *always* uses the original data. the cached previews are a speed optimization for the user interface.

Savageduck
That is how Lightroom Mobile works. It syncs *Smart Previews* in *Smart Collections* from LR5 to LR-M. Any edits, crops, ratings, etc., made in LR-M are synced back to the corresponding LR-M *Smart Collection*. All of those edits are made to previews, as the just isn't room for full size files in the Mobile devices. I have a 64GB iPad2 & a 32GB iPhone 5S. Currently Lightroom Mobile is using 267 MB with 5 Collections & 219 images, all as previews which are quite presentable on the iPad. This makes for a decent portable portfolio where each image retains all the iOS sharing options without the memory load on the iDevice Photos catalog. It always refers back to the original in LR5.

Note: Since all of this is CC managed a CC subscription is required if you are going to run Lightroom Mobile on your iPad/iPhone.