Open Graph Tags Documentation
Facebook requirements for images
The image must be at least 50x50 px (though minimum 200x200 px and maximum 1500x1500 px is preferred) and have a maximum aspect ratio of 3:1. Maximum image size is 5MB. We support PNG, JPEG and GIF formats. Facebook scrapes your page every 24 hours to ensure the properties are up to date.
When does Facebook scrape my page?
Facebook needs to scrape your page to know how to display it around the site.
Facebook scrapes your page every 24 hours to ensure the properties are up to date. The page is also scraped when an admin for the Open Graph page clicks the Like button and when the URL is entered into the Facebook debugger. Facebook observes cache headers on your URLs - it will look at "Expires" and "Cache-Control" in order of preference. However, even if you specify a longer time, Facebook will scrape your page every 24 hours.
Facebook or Twitter does not display images or displays wrong image when sharing link
Make sure that your site is online. Facebbok and Twitter can not read any data from site which can be accessed after login. Go to Joomla Global Configuration and check if Site offline is set to: No. Also check if access to your article is set to: Public.
Enable debug mode in Advanced tab of plugin configuration. Go to you Article page which you want to share and reload it. In message area you will see all Open Graph tags and Twitter Cards tags which were added by this plugin to document header and all images which where found or rejected because them did not meet minimal requirement of Facebook or Twitter.
Copy URL of your page and paste in Facebook debugger or in Twitter Card Validator. You can check if you will find there Open Graph tags and Twitter Cards tags which where outputted by plugin in Debug mode. Also your page will be reloaded in Facebook cache and when you will try again to share a link you will see correct image. If not then Facebook has still old version of your page.
If you have shared your link before installing this plugin you will have to wait until Facebook and Twitter will refresh cache or use Facebook debugger to reload cache.
New post with image is not displayed on Facebook Wall after clicking Like button
Facebook does not post automatically Likes on your Wall. It will only appear in list of all Likes. If you want to show your Like on Wall then you have to add some comment. It is a limitation of Facebook and not of this extension.
Facebook Debugger explanation
Errors That Must Be Fixed
More Than One OG URL Specified: Object at URL 'http://www.perfect-web.co' of type 'article' is invalid because it specifies multiple 'og:url' values: http://www.perfect-web.co, http://www.perfect-web.co.
It means that you have some other Joomla plugin or Template which adds og:url tag. You have to disable those plugin, because you can have only one Open Graph plugin installed or disable option Open Graph site details in Perfect Open Graph Tags.
Like Button Warnings That Should Be Fixed and Open Graph Warnings That Should Be Fixed can be ignored, but it is better to resolve all of them.
URL format for sharing
Enable in Joomla Global Configuration SEF URLs because after clicking Like button popup bubble with publishing on wall might not show.
If you share link with your Joomla! article it can not contain # in URL, because Facebook may link without image.
Examples of correct link:
Examples of bad link:
Twitter requirements for images
The image must be at least 60x60 px will (though minimum 280x150 px). Image will not be cropped unless it has an exceptional aspect ratio. Maximum image size is 1MB.
Twitter Card Validator
Check you page in Twitter Card Validator to see if Twitter recognize Cards on your site or maybe finds some warnings.