WordPress includes seven built in comment gravatar image types, including Mystery Man (a single gray man avatar), a Blank gravatar (so no gravatar), the blue Gravatar.com logo and four computer generated gravatars (random gravatars) called Identicon, Wavatar, MonsterID and Retro.
WordPress built in support for gravatars is straight forward, access the core WordPress Gravatar options under your WordPress Dashboard at “Settings” >> “Discussion” available with all WordPress Themes.
Straight forward options that don’t need much explaining, the first three “Default Avatar” options:
Will use the same local avatar image (these images are located on your sites server within WordPress) for all commenters UNLESS a comment author has registered their email address (the one used for their comment) at https://gravatar.com/ (signup is free).
If a commenter has registered a Gravatar account their avatar image will be served from gravatar.com. For example I’ve registered multiple email addresses with gravatar.com and use the Stallion Image as my avatar (look at comments by “David Law”: that’s me).
The remaining computer generated avatars:
If a commenter uses an email address NOT registered at gravatar.com, the unregistered email address will generate a random gravatar image based on the options set under “Settings” >> “Discussion”.
If you tick the MonsterID option, a random MonsterID avatar will be used. Every email address whether registered, not registered, fake… will generate a unique gravatar avatar that will be used for all that users comments.
Gravatars SEO Value
Unfortunately gravatars from gravatar.com have a negative SEO impact on your WordPress blog, firstly they are images with poor SEO’d filenames and no alt text (fixed in Stallion WordPress SEO 7 and Stallion Responsive 8). And they are loaded from an external site and have an impact on page speed (slow the loading of a page down) (fixed in Stallion Responsive 8).
If you run a page with a number of Gravatars through Google’s PageSpeed Insights Tool (a free tool for checking web page speed) it will indicate where your page speed issues are. Below I’m going to compare Yoasts WordPress Themes web page and the Stallion Responsive Theme page, both have a number of user comments.
Yoast WordPress Theme Page Speed Check
Click either of the two images above to see the entire page speed check results screenshots or check them yourself at the links above each image (links to Google PageSpeed Insights).
Not going to deal with the entire page speed reports, you can see Yoast (which creates the so called best WordPress SEO plugin, ROFLOL) has a poor page speed ranking, 67/100 is NOT a good Desktop result. Stallion Responsive has a respectable 91/100 page speed ranking.
The Yoast page in comparison is filled with issues both on and offsite many of which are related to Gravatar images served from gravatar.com. I guess Joost de Valk (owner of the Yoast site) knows this is an SEO issue as he’s mitigated some of the damage by setting the gravatar under “Settings” >> “Discussion” to “Mystery Man” which means for commenters who haven’t registered at gravatar.com they all use the same Mystery Man avatar image that’s still served from gravatar.com, but it’s one image rather than dozens. If you aren’t a Stallion Responsive theme users I suggest you also set Mystery Man as your avatar.
The Gravatar images on the Yoast site are causing “Leverage browser caching” issues and “Optimize images” issues.
Yoast “Leverage Browser Caching” issues.
As you can see from the image above where I’ve highlighted the gravatar image URLs in green most of the issues are due to images from gravatar.com.
Yoast “Optimize Images” issues.
Like with Leverage browser caching with Optimize images it’s again the gravatar images from gravatar.com.
You will note my website doesn’t have these page speed SEO issues, Google takes page speed into account in it’s ranking algorythm so removing these page speed issues is important SEO wise.
WordPress Gravatar Cache
In Stallion Responsive this SEO issue is fixed by locally caching the gravatar images, basically Stallion downloads a cached version of the avatars to your server which means you have full control over browser caching and image optimization (there are WordPress plugins for optimizing images, I use “EWWW Image Optimizer”).
To cache gravatars on your WordPress blog go to “Stallion Theme” >> “Performance Options” and tick “Gravatar Cache ON**” and set “Gravatar Cache Time” to at least 168 hours (7 days).
The only change you will notice is gravatars are locally cached for 7 days (or whatever you set it at) rather than the default 5 minutes at gravatar.com. If you or a commenter changes the avatar associated with their email address it won’t change on your site for up to 7 days: unless you manually delete the cached avatars using FTP, the cache is at “/wp-content/themes/stallion-responsive/gravatars/” or “/wp-content/themes/stallion-responsive-child/gravatars/” if you use a child theme.
My guess is gravatar.com has set their cache time to a ridiculously low 5 minutes to reduce user support issues, we all know how impatient we are when making changes, if you had to wait even 1 day for a gravatar cache to expire you’d think gravatar.com service had a bug and would contact support :-)
Takes significantly more time to explain this SEO theme feature than actually use it :-)