I tried that – actually I knew from another theme how to do it – and it works. Just upload the pictures into the post and close the upload dialog via the “X” in the upper right corner.
But: You guys at DesignOrbital manage to show the slider also in the blog post overview (http://themes.designorbital.com/contango/blog/) When I setup a slider in a post, it won’t show in the overview 
Is there a setting I miss?
Another question: I love to take – and show – Instagram like square pictures. When I put them in a slider they will have the right width, but the height is reduced to fit a “normal” landscape picture. Is there anything I can do about that?
Thanks. Reiner
P.S.: Arjun – I like your site. Very clean and simple.