I need to be able to add sharing functionality to my custom button. I'm not interested with their generator, as I can't change LinkedIn image there. I want to use my own image for the LinkedIn share button.
Official LinkedIn API for sharing:
https://developer.linkedin.com/docs/share-on-linkedin
Read Terms of Use!
Example link using "Customized URL" method: http://www.linkedin.com/shareArticle?mini=true&url=https://stackoverflow.com/questions/10713542/how-to-make-custom-linkedin-share-button/10737122&title=How%20to%20make%20custom%20linkedin%20share%20button&summary=some%20summary%20if%20you%20want&source=stackoverflow.com
You just need to open it in popup using JavaScript or load it to iframe. Simple and works - that's what I was looking for!
I checked that you can't really embed any video to LinkedIn post, the only option is to add the link to the page with video itself.
You can achieve it by putting YT link into url param:
https://www.linkedin.com/shareArticle?mini=true&url=https://www.youtube.com/watch?v=SBi92AOSW2E
If you specify summary and title then LinkedIn will stop pulling it from the video, e.g.:
It does work exactly the same with Vimeo, and probably will work for any website. Hope it will help.
When you open above links you will see that LinkedIn loads some images along with the passed URL (and optionally title and summary).
LinkedIn does it automatically, and you can read about it here: https://developer.linkedin.com/docs/share-on-linkedin#opengraph
It's interesting though as it says:
If Open Graph tags are present, LinkedIn's crawler will not have to rely on it's own analysis to determine what content will be shared, which improves the likelihood that the information that is shared is exactly what you intended.
It tells me that even if Open Graph information is not attached, LinkedIn can pull this data based on its own analysis. And in case of YouTube it seems to be the case, as I couldn't find any Open Graph tags added to YouTube pages.