I have a simple question about the field «Image URL» in The «SEO Helper» from Joe.
I would like to know what kind of image would be most appropriate to put, a logo of the Company, an image of the page etc. and is there any size to respect?
The image will be what you want to display when someone shares a link to your page. So subject can be what you want.
Facebook Recommends a 1200px x 628px
Facebook also has an excellent tool to check how a share link will look. It also lets “re scrape” the page. That will allow you to refresh what they have cached.