Get the plugin here. Provides a WordPress widget and shortcode to display photos from a public Google Photos album. See a demo and read more about the plugin.

Install as you would any other WordPress plugin.

Go to Appearance -> Widgets and a new widget named Simple Google Photos Grid should be available to use. Drag to your desired widget area and configure.

• Title: Heading of the widget on your site. Default to empty.
• Album URL: The full URL to your public gallery on Google Photos. Ideally should be a short, "shared" link (such as https://photos.app.goo.gl/G8EOLs5YtESchh4g1), but any Google Photos URL should do.
• Num Photos to Show: Even numbers probably work best. There's a maximum number, not sure what it is, but it's pretty low.
• Num Photos per Row: How many photos to show per row? Probably some number that works well with Num Photos.
• Cache Interval (in minutes): How long to cache photo URLs before checking the album on Google again. 0 for no cache.

Place the shortcode in a post, page or theme. [simple_google_photos_grid album-url="https://photos.app.goo.gl/G8EOLs5YtESchh4g1"]

Available attributes are:

• album-url: (required) the url to a public Google Photos album
• number-photos: (optional) number of photos to display, defaults to 4
• number-photos-per-row: (optional) number of photos per row, defaults to 2
• cache-interval: (optional) length, in minutes, to cache the photo urls retrieved from Google, defaults to 15

[simple_google_photos_grid album-url="https://photos.app.goo.gl/G8EOLs5YtESchh4g1" number-photos="6" number-photos-per-row="3" cache-interval="120"]

Your album on Google Photos must be "public", which means you need to go into Google Photos on the web and set "Sharing options" to on, i.e. "Anyone with the link can see these photos and the people who've been invited or joined."

Google Photos Public Sharing Settings:

This plugin is pretty hacky since the above doesn't really make the album public in the sense that Picasa used to, or Flickr does, etc. Anyway, there is no reliable Google Photos api. The Picasa API is broken and doesn't list new albums made in Photos, and not all albums show up in Google Drive. So, read this and this if you're interested in this mess.

No support is provided. Probably no features will be added. You are free to ask, or to fork. Pull requests accepted.