I installed K2 and then installed SIG (non-pro) and get this message:

"Notice: Please install the Simple Image Gallery (Free/Pro) plugin if you want to use the image gallery features of K2!"

I'm sure I've done something wrong but want to try the free version before buying the Pro.  any ideas?

Same issue here.

Looks like no one pays attention to these galleries, months later.

I found the solution on the K2 site.  Make a copy of jwsig.php in the plugins/content folder and name it jw_sig.php upload it back to that folder and it fixes the problem.  Seems to need the underscore in the name.