How does NGFB find / detect / select images?

The images used in the Open Graph, Rich Pin, Twitter Card, etc. meta tags are chosen in this sequence:

  1. An image defined in the custom Social Settings metabox Image ID or Image URL field (Pro version).
  2. An e-commerce product image from a supported 3rd-party plugin (Pro version).
  3. A featured or attached image from the WordPress Media Library or NextGEN Gallery v2. Featured images are selected before attached images, and NextGEN Gallery v1 featured images are supported in the Pro version (NGG v1 featured images require additional media integration features).
  4. An image from the NextGEN Gallery ImageBrowser in combination with an nggalbum or nggallery shortcode (Pro version).
  5. A preview image from a NextGEN Gallery nggalbum or nggallery shortcode (Pro version).
  6. Image(s) from expanded NextGEN Gallery singlepic, nggallery, nggtags or ngg_images shortcodes.
  7. Image(s) from <img/> HTML tags in the content text.
    1. NextGEN Gallery <div|a|img/> HTML tags with the ‘data-ngg-pid‘ (automatically added by NGFB) or ‘data-image-id’ attribute (Pro version).
    2. <img/> HTML tags with the ‘data-wp-pid‘ (automatically added by NGFB) attribute for media Library Images.
    3. Any other <img/> HTML tag with a ‘data-lazy-src’ or ‘src’ attribute.
  8. A default / fallback image defined on the SSO General settings page.

Most of these methods will lead to a properly sized image with correct dimensions since the image ID can be determined (provided the original image is large enough). Always upload the largest images you can to the Media Library and/or NextGEN Gallery, and let WordPress create the re-sized / smaller versions as required. If an original image is smaller than the required Image Dimensions, it may be ignored by the plugin – so always upload the largest images possible.

See the Setup Guide for additional information on image related settings.