If one or more
<img/> HTML tags is being ignored, it's probably because the image
width and height attributes are missing, or their values are less than
the Image Dimensions you've chosen on the settings page(s). NGFB will only use an image equal to, or larger than, the Image Dimensions you've chosen.
If you want to display smaller image thumbnails in your content, and still have NGFB use the larger versions of those thumbnails, you can add a "data-share-src" attribute with a URL to the larger image. For example:
<img data-share-src="http://underwaterfocus.com/wp-content/gallery/cache/40_crop_200x200_20080514-152313-mevallee-2951.jpg" src="http://underwaterfocus.com/wp-content/gallery/2008-05-bonaire-na/thumbs/thumbs_20080514-152313-mevallee-2951.jpg" width="150" height="150" />
The order in which the
attributes are listed is important -- place the 'data-share-src'
attribute before the 'src' attribute to give it a higher priority. If
you do not want (or cannot add) a 'data-share-src' attribute to the
HTML tag, and would like NGFB to share smaller image thumbnails (not
recommended), you can uncheck the 'Ignore Small Images' option on the
Advanced settings page.
Please make sure the 'data-share-src' is large enough - preferably 1200x630px or larger. See Facebook's Maximizing Distribution for Media Content article for more information on open graph meta tags and image sizes. Facebook recommends an image size of 1200x630px, 600x315px as a minimum, and will ignore any images less than 200x200px.