With lightroom (not the desltop one, the mobile one), you have to "upload" photos first, and this counts to your quota (20GB for the real lightroom subscribers).
1. When you upload photos, does it upload a low res copy, or the original file? I know when you "sync" images in lightroom desktop its a low res copy.
2. Is there a difference between the the web version of lightroom, and the download version of the web version?
2.1 Is there any functionality difference?
2.2 can the download versoin of the mobile version work with local (not uploaded files?)
Basically, I am stuck somewhere with very slow upload speeds, and a feeble pc which might not be able to run the full version of lightroom, so am considering using the mobile version.
3. This is where it gets complicated. If I upload photos via the web version, and they are indeed low res copies (thus being faster to upload), then later import the photos intot he full desktop version when I get home, how can I reconcile the full res imported photos, with the uploaded ones in the web version? i.e syncronise the edits and keywords?
1. Lightroom Mobile always uploads full res images to the Cloud. (Note: Lightroom Mobile cannot run on PCs, Lightroom CC Desktop can though)
2. Not quite sure I understand the question. Do you mean is there a difference between Lightroom CC Web (accessed through a browser) and Lightroom CC Desktop (the downloadable app... not to be confused with Lightroom CC Classic)?
If so, in respect to use with the Cloud, both upload full res Originals.
3. The only way you can upload lower res photos to the Cloud is to use Lightroom Classic. If you use Classic you could sync a Collection to the Cloud, this will upload lower res Smart Previews of photos in that Collection. If you require the full res in the Cloud at a later date, you can import them into Lightroom CC Desktop and the Smart Previews in the Cloud will be overwritten but will retain edits etc. (Note: Any Edits made in Classic will Sync to the Cloud and Vice Versa. Keywords mostly don't though so it may be best to apply them in your primary workplace, either the Cloud or Classic).
Basically there is a Cloud Ecosystem (CC Desktop, CC Mobile, CC Web) that uploads all photos full res. The traditional Lightroom Classic only uploads Smart Previews and then only ones put in a synced Collection