The one step many people new to WordPress and Gravatar miss is tying your WordPress.com account to your Gravatar account if you do this correctly  then you should  automatically get your profile  image on the posts you setup similar to this article from the Huff Post.

https://www.huffingtonpost.com/entry/sean-spicer-trump-mueller-witch-hunt_us_5b50927ce4b0b15aba8c4265

Here is all it takes to setup.

1. Go to the Gravatar Website and sign up
   1. http://gravatar.com is the website
   2. Go to “Create Your Own Gravatar”
2. You’re going to enter your email address and click the button “Get Your Gravatar”
   1. It will give you options of where you want to upload an image from for your Gravatar
3. They will send you a confirmation email once you have signed up and submitted everything and they will give you an option on how you want to input your image.
4. Once you have confirmed and signed in they will give you a cropping option for your image and then click “Crop and Finish”
5. Next, choose your rating on how you think you image content is showing.

Once you’re done, you can start to use your avatar when you visit websites that enable it. It should always appear as an option when visiting websites