如何显示特定的图片作为缩略图，同时在 Facebook 上实现共享？

This blog post seems to have your answer: http://blog.capstrat.com/articles/facebook-share-thumbnail-image/

Specifically, use a tag like the following:

<link rel="image_src"
type="image/jpeg"
href="http://www.domain.com/path/icon-facebook.gif" />

The name of the image must be the same as in the example.

Click "Making Sure the Preview Works"

Note: Tags can be correct but Facebook only scrapes every 24 hours, according to their documentation. Use the Facebook Lint page to get the image into Facebook.

http://developers.facebook.com/tools/lint/

I was having the same problems and believe I have solved it. I used the link meta tag as mentioned here to point to the image I wanted, but the key is that if you do that FB won't pull any other images as choices. Also if your image is too big, you won't have any choices at all.

Here's how I fixed my site http://gnorml.com/blog/facebook-link-thumbnails/

My tags were correct but Facebook only scrapes every 24 hours, according to their documentation. Using the Facebook Lint page got the image into Facebook.

Enter your URL here and FB will update the metadata from your page:

https://developers.facebook.com/tools/debug (updated link)

From Facebook's spec, use a code like this:

<meta property="og:image" content="http://siim.lepisk.com/wp-content/uploads/2011/01/siim-blog-fb.png" />

Source: Facebook Share

Sharing on Facebook: How to Improve Your Results by Customizing the Image, Title, and Text

From the link above. For the best possible share, you'll want to suggest 3 pieces of data in your HTML:

• Title
• Short description
• Image

This accomplished by the following, placed inside the 'head' tag of your HTML:

• Title: <title>INSERT POST TITLE</title>
• Image: <meta property=og:image content="http://site.com/YOUR_IMAGE.jpg"/>
• Description: <meta name=description content="INSERT YOUR SUMMARY TEXT"/>

If you website is static HTML, you'll have to do this for every page using your HTML editor.

If you're using a CMS like Drupal, you can automate a lot of it (see above link). If you use wordpress, you can probably implement something similar using the Drupal example as a guideline. I hope you found these useful.

Finally, you can always manually edit your share posts. See this example with illustrations.

I also had an issue on a site I was working on last week. I implemented a like box and tested the like box. Then I went ahead to add an image to my header (the ob:image meta). Still the correct image did not show up on my facebook notification.

I tried everything, and came to the conclusion that every single implementation of a like button is cached. So let's say you clock the Like button on url A, then you specify an image in the header and you test it by clicking the Luke button again on url A. You won't see the image as the page is cached. The image will show up when you click on the Like button on page B.

To reset the cache, you have to use the lint debugger tool that's mentioned above, and validate all the Urls for those that are cached... That's the only thing that worked for me.

Facebook uses og:tags and the Open Graph Protocol to decipher what information to display when previewing your URL in a share dialog or in a news feed on facebook.

The og:tags contain information such as :

• The title of the page
• The type of page
• The URL
• The websites name
• A description of the page
• Facebook user_id's of administrators of the page ( on facebook )

Here is an example ( taken from the facebook documentation ) of some og:tags

<meta property="og:title" content="The Rock"/>
<meta property="og:type" content="movie"/>
<meta property="og:url" content="http://www.imdb.com/title/tt0117500/"/>
<meta property="og:image" content="http://ia.media-imdb.com/rock.jpg"/>

Once you have implemented the correct markup of the og:tags and set their values, you can test how facebook will view your URL by using the Facebook Debugger. The debugger tool will also highlight any problems it finds with the og:tags on the page or lack there-of.

One thing to keep in mind is that facebook does do some caching with regard to this information, so in order for changes to take effect your page will have t be scraped as stated in the documentation :

Editing Meta Tags

You can update the attributes of your page by updating your page's tags. Note that og:title and og:type are only editable initially - after your page receives 50 likes the title becomes fixed, and after your page receives 10,000 likes the type becomes fixed. These properties are fixed to avoid surprising users who have liked the page already. Changing the title or type tags after these limits are reached does nothing, your page retains the original title and type.

For the changes to be reflected on Facebook, you must force your page to be scraped. The page is scraped when an admin for the page clicks the Like button or when the URL is entered into the Facebook URL Linter Facebook Debugger...

I see that all the answers provided are correct. However, one important detail was overlooked: The size of the image MUST be at least 200 X 200 px, otherwise Facebook will substitute the thumbnail with the first available image that meets the criteria on the page. Another fact is that the minimum required is to include the 3 metas that Facebook requires for the og:image to take effect:

<meta property="og:title" content="Title of the page" />
<!-- NEXT LINE Even if page is dynamically generated and URL contains query parameters -->
<meta property="og:url" content="http://yoursite.com" />
<meta property="og:image" content="http://convertaholics.com/convertaholics-og.png" />

Debug your page with Facebook debugger and fix all the warnings and it should work like a charm! https://developers.facebook.com/tools/debug

The easiest way I found to set Facebook Open Graph to every Joomla article, was to place in com_content/article/default.php override, next code:

$app    = JFactory::getApplication();
$path   = JURI::root();


$document = JFactory::getDocument();
$document->addCustomTag('<meta property="og:title" content="YOUR SITE TITLE" />');
$document->addCustomTag('<meta property="og:name" content="YOUR SITE NAME" />');
$document->addCustomTag('<meta property="og:description" content="YOUR SITE DESCRIPTION" />');
$document->addCustomTag('<meta property="og:site_name" content="YOUR SITE NAME" />');
if (isset($images->image_fulltext) and !empty($images->image_fulltext)) :
$document->addCustomTag('<meta property="og:image" content="'.$path.'<?php echo htmlspecialchars($images->image_fulltext); ?>" />');
else :
$document->addCustomTag('<meta property="og:image" content="'.$path.'images/logo.png" />');
endif;

This will place meta og tags in the head with details from current article.

Here’s how this works all:

1. You need the ability to access the HTML on the particular webpage you are sharing. It'll probably work site wide too if you use a common header file. I have not tried this, but it should work. You'll just get the same image for all pages if you do this though.

2. You need to add these HTML meta tags into page in the . It will not work if you put it in the . Make sure to customize per your a) image, b) description, c) URL, and d) title.

A Real Example.

<meta property="og:image" content="http://www.coachesneedsocial.com/wp-content/uploads/2014/12/BannerWCircleImages-1.jpg" />


<meta property="og:description" content="Coaches share their secrets to success so you can rock 2015." />


<meta property="og:url"content="http://www.coachesneedsocial.com/coacheswisdomtelesummit/" />


<meta property="og:title" content="Coaches Wisdom Telesummit" />

3. Save
4. Open a fresh Facebook post, and retry the page you wanted to share.
5. If you are having trouble… you can debug it with this Facebook tool. It looks more geeky than it is. It tells you what Facebook is seeing when you post in the URL to share.

https://developers.facebook.com/tools/debug/og/object/

Big Tip.. make sure the “quote marks” are the same in your HTML (they should look like 2 straight marks and no curves… sometimes programs change these to different fonts and it goofs up the code.