This has been completed, and rolled into the Modern Thumbnails.
It was recently brought to our attention in July 2019 that Google's requirements for featured images have changed on articles and recipe posts.
A minimum 300,000 pixels square image translates to a 548x548 image.
Update 2020/01/11 - Google has now change it to 800,000 pixels minimum, which is roughly 900x900. This is why we recommend actually using 1200x1200 instead of Google's minimums.
We'll be looking into adjusting our featured image recommendations (which control the thumbnails generated on the homepage + category page) to by compliant with search engine requirements. Specifically:
- Only a marked-up image that directly belongs to the article should be specified, not generic site-wide images.
- (Featured) Images should be at least 1200 pixels wide (and 1200 pixels high for 1:1 ratio)
- Every page must contain at least one image (whether or not you include markup). Google will pick the best image to display in Search results based on the aspect ratio and resolution.
- Image URLs must be crawlable and indexable.
- Images must represent the marked up content.
- Images must be in .jpg, .png, or .gif format.
- For best results, provide multiple high-resolution images (minimum of 300,000 pixels when multiplying width and height) with the following aspect ratios: 16x9 (landscape), 4x3 (landscape), and 1x1.
The big change here is that the sizes being recommended (16x9 and 4x3) are LANDSCAPE (wider than tall) and the final option (1x1) is a square. It's also worth noting that there's a minimum 548x548 dimension - this is likely too small to last, and we expect Google to increase this over time.
If the current article requirement is 548x548, why are we recommending 1200x1200?
Because Google is known for changing things when it suits them. The current AMP requirement is 800,000 pixels, which is 895x895, and we have no reason to believe that this won't be applied to the rest of the web at some point.
Edit: as of 2020/01/14 Google has changed AMP images to minimum 1200px width required. We're already seeing this happen.
If we recommended 900x900 (810,000 pixels) and Google suddenly decided they wanted 1,000,000 pixels, it would suddenly be outdated again.
For safety sake, recommending 1200x1200 for the featured image gives us us 1,440,000 pixels, which provides some breathing room for future changes.
It was brought to our attention by Casey Markee that Google discover calls for 1200px width minimum featured images for full compatibility.
This may lead to traffic increases for sites seeing low adoption and numbers in their Google Search Console:
This further reinforces our opinion above that they'll move to these required dimensions for all featured images in the future.
When you get a "recipe results" in search engine, Google uses the image specified in the recipe card. This is different than the image specified as the "featured image". At this time, we believe that all recipe cards automatically crop images to be compliant with recipe schema.
Related: how thumbnails work
The notable difference is that recipe cards only have a required dimension of 300x300 instead of 1200x1200 for schema.
What's an article? Anything that isn't marked up with recipe schema (from plugins like WPRM, Tasty Recipes and Create) or other schema, is likely to fall under the "article" schema that gets output by default by Yoast.
Full specification: https://developers.google.com/search/docs/data-types/article#article_types
Your featured image is automatically specified on the post page, in the document header.
Does my featured image need to match the recipe card?
No. They don't need to according to current requirements.
My personal recommendation though, would be absolutely.
It's just less to think about, and lets you simplify your life.
This is one of those things where if you can simplify, do it.
It's MUCH easier to move forward knowing that the featured image should be 1200x1200 and use the same image for the recipe card.
This cuts down on the work involved with each post (creating and saving two separate images for EACH POST), as well as the mental overhead involved with creating a post (remembering multiple image sizes, having to take pictures that look good in portrait AND square).
What size and orientation would you recommend?
Moving forward, we will be recommending square featured images with a minimum 1200x1200px size, to be compliant with Google's article schema requirements.
This will mean creating a separate 1200x1200 image specifically to use as a Featured Image, which will then be used to generate thumbnails on the homepage and category pages.
Because none of these pages use the full 1200px width, you should have no problem generating appropriately sized images.
Portrait was, and is still the dominant orientation used by food bloggers. This is partly due to Pinterest's influence, and partly due to the sizes we put in place years ago based on user feedback. This isn't a bad thing, it's just the reality of the situation.
We also took a poll in the Food Bloggers Central Facebook group a week ago (unrelated to this) to learn how people are using images within the post (unrelated to featured images):
About two thirds of people use both portrait and landscape images in their post.
But more revealing was the discussion around the images. People still feel the need to put a Pinterest image in the post (which has to comply with Pinterest dimensions requirements - portrait), but the landscape images were discussed as more reader-friendly.
This is because portrait photos require a lot of scrolling on the user's part. Remember that roughly 80% of pageviews are now mobile, and you should be designing your posts for mobile phones, not desktop.
Landscape or square photos have another benefit of being smaller in size (dimension-wise), which means their filesize (the KBs) are smaller, which speeds up page loads.
Do I need to update all my previous posts with new featured images?
The unpleasant answer here is yes, it would be a good idea.
The reality of the situation is that this is a ton of work, and isn't urgent. Most images used for recipe posts are pulled via the recipe card, which are compliant as far as we're aware.
We'd place this as a good optimization, but low priority task. Updating post content and writing better recipe posts is more important than this, for example.
If you'd like to "correct" the featured images, my recommendation would be to go to your Google Search Console, find the top 10 pages that send traffic to your blog, and update those.
Any page that is sending 0% - 0.5% of your traffic can be put on the back-burner in favor of more important work.
How do I know if this is an issue?
If the images being displayed for your search result are not the images you've specified in the recipe card (or featured image, if no recipe card), then Google has decided that one of your other pictures are more "correct" (eg. the dimensions and format matches - a square or landscape photo with specific dimensions), or has decided that your images don't qualify to be displayed alongside the search results.
Google does not throw an error or warning in Google Search Console for this, which is unfortunate.
Thanks to Claire McEwen for bringing this to our attention, and Casey Markee for additional guidelines.
Update 2020/04/14: we may look into registering additional thumbnails and extending Yoast to automatically output the article schema required thumbnails.