Lightroom is currently consuming over 1.5GB on my iPhone. I have 40 collections with about 150 photos that I deliberately sync from desktop. BUT - I have 1141 photos under "Lightroom Photos" and I'm not sure how they got there?! I don't want to delete if it means I lose them from my master catalog. I don't see any easy way to delete since this isn't a Collection and there's no Remove option. To make it worse there now seem to be RAW files which i assume are taking even more space.
i think some of the Lightroom Photos may have been imported from camera roll. Others may have come in via Eye-fi app or my lightening SD connection (pretty sure this was source of Raw images). All of these were also imported from the SD Card into Lightroom CC on my desktop, so ... If I delete on iPhone, I hope it won't sync the deletions up to my catalog and blow away the images there?
It could be that you have camera roll set to auto-sync. That means every new photo you take is synchronized with LR desktop. You should be able to delete photos from the mobile device and those already synchronized will remain on your computer. Check the folders tab in the LR Library – not the collections tab.
I believe you're right, that's what created the problem. I looked at the folders in LR on my PC ... There are a few of them related to iPhone, iPad ... But these contain far less than 1141 photos so I'm still not sure how images in LR mobile relate back to my Catalog.
I'll try to test, delete a few on iPhone and see if they disappear from the (iPad, iPhone) folders on PC. If they do, that's good. I also have same images imported from SD card on the PC ... I'm assuming (hoping) these would not be affected by deleting the ones on LR mobile? Again, I'm not deleting the ones in synced Collections, just the ones under "Lightroom Photos" that apparently auto synced to LR Mobile on the iPhone.
It's cool that LR keeps edits in sync across devices ... Less cool that it's not clear how to keep things clean on mobile device without adverse impact on Catalog. It would be nice to have a tutorial or writeup on file mangement.