Add meta image tags (DT-1911)

[mgiraldo]

Add og:image, og:image:alt, and twitter:image:alt tags to all pages. This is for social media integration. Details are here: https://digitalpubliclibraryofamerica.atlassian.net/wiki/spaces/TECH/pages/122519660/HTML+Metadata+Tags+for+SEO+and+Social+Media

Creator: Audrey Altman
Reporter: Audrey Altman

[mgiraldo]

Open graph requires full URLs (as opposed to relative URLs) so ideally we need a way to manage the base URL of the site without hard-coding it.

By: Audrey Altman

[samanthadpla]

Hi Team - just making a plug to move this up in priority -- it would be great to even just have the DPLA logo show up on links shared via social media instead of this default grey box/icon (Example tweet: https://twitter.com/dpla/status/1009135030394933249).

Not sure if this is a larger ask, but adding a short content snippet preview would also be great. (Example tweet: https://twitter.com/dpla/status/1007261461671022592)

[mgiraldo]

@samanthadpla where do you suggest we take the content snippet? eg: “X characters from post description”

[mgiraldo]

gonna use "The Digital Public Library of America brings together the riches of America’s libraries, archives, and museums, and makes them freely available to the world." for now (from Jira: https://digitalpubliclibraryofamerica.atlassian.net/wiki/spaces/TECH/pages/122519660/HTML+Metadata+Tags+for+SEO+and+Social+Media)

[samanthadpla]

@mgiraldo sorry for delay -- yes, ideally i would have said the except field for blog posts at least.