Dealing with an almost full iPhone

I recently attached an iPhone for syncing up Photos onto Mylio.

The library was huge, and by the time it was half way done, Mylio mentioned about storage full (and that was about 10GB free storage left from the iPhone).

Any suggestion in this situations? Will they continue to sync slowing, or refuse to continue syncing until further action?

From the general suggestion, I see a “clear cache” option from other forum post but…
I’ve already cleared most preview pictures from the iPhone storage (it takes thumbnails only, for min. storage footprint).
The “clear cache” option also mentioned “Original”… does it refer just a cache, or the actual original photos in the iPhone Photo Library?

I would like to seek for way to get this iPhone coming get picture sync and protected, but before it is getting done, I’m not quite willing to touch anything currently in its iPhone Photo Library.

In the device settings, you can set how much free space Mylio leaves your phone, which is why you still have 10 GB to play with if I had to guess. If you decrease it, you’ll have a little more room.
I do fight this all the time though. My next phone will just have to be bigger - 64GB doesn’t get you far these days.