I've done a fair amount of past research around good image viewers for mobile (especially open source) and on the surface this update to Photoswipe appears to move the solution ahead of many competitors.

The original version of Photoswipe was a great image viewer, but unfortunately was not well maintained. This new version that the developer has taken over really leapfrogs over other viewers.

The key is will it be maintained and be able to keep up with a fast changing mobile landscape? Or should I continue using the current paid solution I'm using today (Foobox). While Foobox is not up to par to this solution, it will be interesting to see where Photoswipe is 6 to 12 months down the road. For me, having a well maintained solution is worth the $30