How can I add a default og:image if the image is missing?

@dudley 

If you want to add a default og:image when the specified image is missing or cannot be loaded, you can do so by adding a fallback image in the og:image tag.

Here is an example of how to add a default og:image using HTML and the Open Graph protocol:

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<meta property="og:image" content="https://example.com/image.jpg" />
<meta property="og:image:width" content="1200" />
<meta property="og:image:height" content="630" />

<!-- fallback image in case the specified image is missing -->
<meta property="og:image" content="https://example.com/fallback-image.jpg" />
<meta property="og:image:width" content="1200" />
<meta property="og:image:height" content="630" />

In the example above, we have specified two og:image tags. The first one is the image that you want to use as the default image, and the second one is the fallback image that will be displayed if the first image is missing or cannot be loaded.

Make sure that the dimensions (width and height) of both images are the same to ensure that the image is displayed correctly on social media platforms.

By adding a fallback image, you ensure that your website always has an image to display when it is shared on social media, even if the specified image is not available.

@dudley 

Additionally, you can also handle the fallback image using JavaScript. Here's an example:

1. Add an id to your og:image tag in the HTML:

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<meta property="og:image" id="og-image" content="" />

1. Create a JavaScript function that checks if the image is missing and sets the fallback image:

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function setFallbackImage() {
  var ogImage = document.getElementById("og-image");
  
  // Check if the image is missing or cannot be loaded
  if (!ogImage.complete || typeof ogImage.naturalWidth === "undefined" || ogImage.naturalWidth === 0) {
    ogImage.content = "https://example.com/fallback-image.jpg";
  }
}

// Call the function
setFallbackImage();

In this example, the function setFallbackImage checks if the specified image is missing or cannot be loaded. If the image is missing, it sets the content of the og:image tag to the fallback image URL.

Remember to replace "https://example.com/fallback-image.jpg" with the URL of your fallback image.

By using JavaScript, you have more control over how the fallback image is determined. You can customize the logic based on your specific requirements, such as checking for specific error codes or using different fallback images for different pages.

@dudley 

To summarize, there are two ways to add a default og:image if the specified image is missing:

1. HTML/Open Graph Protocol: Add a fallback image in the og:image tag, specifying its URL, width, and height. This way, the fallback image will be used if the specified image is not available.

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<meta property="og:image" content="https://example.com/image.jpg" />
<meta property="og:image:width" content="1200" />
<meta property="og:image:height" content="630" />

<meta property="og:image" content="https://example.com/fallback-image.jpg" />
<meta property="og:image:width" content="1200" />
<meta property="og:image:height" content="630" />

1. JavaScript: Use a JavaScript function to check if the specified image is missing or cannot be loaded. If it is, update the content of the og:image tag to the URL of the fallback image.

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function setFallbackImage() {
  var ogImage = document.getElementById("og-image");
  
  if (!ogImage.complete || typeof ogImage.naturalWidth === "undefined" || ogImage.naturalWidth === 0) {
    ogImage.content = "https://example.com/fallback-image.jpg";
  }
}

setFallbackImage();

Remember to replace "https://example.com/fallback-image.jpg" with the URL of your fallback image.