To instantly use an image as a puzzle, the "Parameterized Puzzles" now has the option (in the puzzle selector) to let you select an image file from your computer to be used as a puzzle. You can then change any of the settings, such as the number of pieces, as usual.

To create an animated puzzle, select "Puzzle Pack Editor" from the main menu to bring up the new GUI for creating puzzles.
This UI lets you create packs of puzzles and modify the settings for each puzzle in the pack. Unlike the simpler option, you can also adjust animation settings and even select a shader to be used as a puzzle.

Restored missing text in "about this game"
Can rotate the piece being dragged.
Panning the view is now reliable at slow speed.