Thanks for trying the plugin, are you using static data to generate the image or are you using live data from the Amazon site?
If you're using static data then you need to manually add the information needed by the 'image' template in the shortcode. For example:
[amazon asin=1857231384&template=image&title=Consider Phlebas (The Culture)&image=http://ecx.images-amazon.com/images/I/51TrnvvDCLL.jpg]
I have provided the title, and url for the image in the shortcode.
If you're using live data then you must have a valid set of AWS access keys and have entered them on the settings page.
If this does not help then try posting the shortcode you are using here, or enable the 'debug' option in the plugin settings and put a link to your site here.
Some aspects of the plugin are only available once the Amazon Web Service keys are provided - it could be this is why some items mentioned in the FAQ are not shown in your version? Or it could just be I have not kept the FAQ up to date, is there anything in particular is missing?
Hope this helps!