Hi PG;

Resetting that liner may well be possible. But, it DEFINITELY will not be a simply matter of just adding water. Roughly speaking, here's the process:

#1. Use a vacuum, with a hose taped behind the liner to 'suck' it into place.
#2. As it is pulled in, make sure the points already connected (returns, skimmer, main drain?) are not stressed. Typically, this will require 'tugging' the liner in to place.
#3. Work the wrinkles out of the liner as much as possible.
#4. Begin filling; monitor wrinkles & stress; adjust liner as needed.

I've hung a liner a couple of times, and made adjustments more times than that. But, I've never tried to do it to a liner that's been in place a couple of years. So, I can't estimate your chances of success. However, your liner does not look like many I've seen, where they were seriously overstretched on installation. That increases your chance of being able to reset it -- though it also increases the chance that you'll have some permanent wrinkles.

Ben