First off, I don't have the comma problem in this version of WP. I deactivated the plug-in Gallery Press and now I can see my gallery in the post.
I found in the Miscellaneous settings panel where it states the size of the thumbnail, and the medium thumbnail. There's no option for "full" size image.
I like for my posts to contain the full size images as that eliminates the need for the viewer to click through 2 more times to see a full-sized image.
In order to get the full-sized images into the body of the post, I have to manually select "full" and then enter into post. This effectively negates the efficiency of the '[gallery]' option.
Am I missing something obvious here?