Method 1
To change the image that appears when your Blogger site is shared on social media, you can follow these steps:
Go to your Blogger dashboard and select the blog you want to edit.
Click on the "Settings" tab in the left-hand menu.
In the "Basic" section, scroll down to the "Meta tags" subsection.
Look for the "Description" field, and add a short summary of your blog or post.
Look for the "Image" field, and enter the URL of the image you want to use as the thumbnail when your blog or post is shared on social media.
Save your changes and publish your post.
Note that social media platforms may cache the image and description of your blog or post, so it may take some time for the changes to take effect. You can use a tool like the Facebook Sharing Debugger or the Twitter Card Validator to force the platforms to refresh their caches and show the updated image and description
Method 2:
Choose the image you want to use: First, select an image that you want to use as the thumbnail when your blog or post is shared on social media. This image should be relevant to your blog or post, and it should be visually appealing to attract clicks.
Upload the image to your blog: Upload the image to your Blogger site by clicking on the "New post" button, then clicking on the "Insert image" icon in the post editor. Choose the image you want to use from your computer, and click "Add selected."
Copy the image URL: Once the image is uploaded to your blog, right-click on the image and select "Copy image address" (or similar). This will copy the URL of the image to your clipboard.
Go to your Blogger dashboard: Open your Blogger dashboard and select the blog you want to edit.
Go to the "Settings" tab: Click on the "Settings" tab in the left-hand menu.
Edit the meta tags: In the "Basic" section, scroll down to the "Meta tags" subsection. Look for the "Description" field, and add a short summary of your blog or post. Then, look for the "Image" field, and paste the URL of the image you want to use as the thumbnail when your blog or post is shared on social media. Make sure that the URL is valid and points to the correct image.
Preview the changes: Click on the "Preview" button to see how your blog or post will look when shared on social media. Check that the image and description are correct and look good.
Save and publish: Finally, save your changes and publish your post. Note that social media platforms may cache the image and description of your blog or post, so it may take some time for the changes to take effect. Use a tool like the Facebook Sharing Debugger or the Twitter Card Validator to force the platforms to refresh their caches and show the updated image and description