Problems with NextGen gallery

A few problems I’d really appreciate some help with please.

1) All images are uploaded as thumbnails so I cannot get a larger size.

2) I can’t resize the thumbnails images. I’ve edited the size in Options and then gone to Manage and selected Resize in the drop down.

I also tried this with a single larger image and the same result.

3) Looking in WP image manager, it shows a tab for Nextgen. When I go there and select the gallery name, click save, it immediately goes back to No gallery.

4) Should the code be [nggallery id=1] or [gallery=1]?

5) The thumbnail that is shown on the page has [Show as slideshow]. How can I get rid of that as I want static images.

Sorry there are so many questions.

Thanks