Sorry for some delay with reply. Images could be blurry if you have big size images but images quality in gallery settings set in medium by default, try to set large value.
Open gallery settings / scroll down to the Gallery size options / Thumbnails options / Thumbnails Quality.
Please try and let me know if you’ll have some other questions.
Also I wish you to know that right now we’re working on Robo Gallery version 3.0 release which will include so much of new functions, for example Instagram feed, youtube channels and playlists support, gallery comments, image rating, new gallery hover effects , new layouts, visual layout builder, visual hover effects builder and much much more. Password protected gallery planned as add-on for the gallery.