Hi i'm new to k2. I installed JoomlaWorks 'Simple Image Gallery' Plugin v3.0.0 for Joomla!  the free one each time i try to upload in image gallery i got the msg "Notice
Notice: Please install JoomlaWorks Simple Image Gallery Pro plugin if you want to use the image gallery features of K2!"

can anyone help ?

The free version of the plugin doesn't work with K2 Image Gallery functionality. You will have to get the Pro version, as the message states.