With Facebook and LinkedIn, a link preview is shown in the composer when scheduling a post, allowing you to see (more or less) what your post will look like once it's been published. It's a bit more difficult with Twitter, since we are not currently able to load a preview of the post.
That said, depending on whether or not Twitter cards are enabled on the website you're sharing a link to, your tweet may end up looking a bit more like what you've come to expect from link previews on platforms like Facebook and LinkedIn.
What are Twitter Cards?
Do you ever wonder why some tweets look a bit plain, while others are more attention grabbing and include richer media experiences? Twitter Cards are an alternative format for tweets, where rich photos, videos and media experiences can be added to tweets, helping to drive more traffic to a website.
It's important to note that Twitter Cards are not something that you (the end user) can choose to add to a tweet. They are automatically generated for your tweets if Twitter Cards are enabled on the website that you're sharing a link to. Twitter Cards are enabled on a website by adding some specific HTML markup to the HEAD section of a page. Learn more about Twitter Cards here.
You can use Twitter’s Card Validator tool to preview how a link you're planning to share will be displayed once published on Twitter.
What will my tweets look like once published?
Posts that include a link but no image, will be published as Twitter Cards if Twitter Cards are enabled on the site you're sharing a link to, as shown below.
If Twitter Cards are not enabled on the site you're sharing a link to, the post will be published as a regular text post, without an image.
Link and image
Posts that include both a link and an image, will appear as image posts once published to Twitter. Chosen images (either selected from the Suggested media or uploaded), will always override Twitter Cards.
In the example below, the link shared was to an article published on https://buffer.com/resources/. Twitter Cards are enabled on this site, but because an image was chosen, the Twitter Card was overridden.
Posts that include an image but no link, will appear as image posts, as shown below.