Hm. You have some serious issues…
The following code appears BEFORE the <!DOCTYPE html>
element — that’s a big no-no:
<div style="position:relative; background-color:#000; padding:5px; z-index:9999999" align="center"><img src="http://www.larisaevents.gr/wp-content/uploads/2015/11/eol-banner.jpg" width="800" /></div>
Do a view source in Firefox — errors are highlighted in red. Or use the W3C validator at https://validator.w3.org/.
Your NGFB meta tags do not contain an image. Did you get a warning about your image dimensions being too small? Here’s some info on how NGFB selects images: http://surniaulula.com/codex/plugins/nextgen-facebook/faq/how-does-ngfb-find-detect-select-images/
Let me know if you have any questions.
js.
That webpage has the following og:image:
<!-- og:image:1 --><meta property="og:image" content="http://www.larisaevents.gr/wp-content/uploads/2015/11/butler-600x315.jpg"/>
<!-- og:image:1 --><meta property="og:image:width" content="600"/>
<!-- og:image:1 --><meta property="og:image:height" content="315"/>
Is this incorrect? You didn’t say.
Have you run the Facebook debugger on that webpage? You have some serious HTML issues that must be resolved. If the Facebook crawler cannot parse your HTML, then it cannot see the meta tags. Fix your HTML.
js.
