Recently someone asked me how to choose what image shows up on the blog page. The key is to set your featured image in WordPress for that specific blog post.
In this quick tutorial I will show you how to do just that.
Bonus: Download a free checklist of the first plugins that I always install on a new WordPress Blog.
The image below is a screenshot of my blog page, where my featured images show up.

Step 1: Open a blog post
Step 2: Click on "Set featured image" (Scroll down on the right)

Step 3: Select an image from your media library or upload to your media library.
Note: Make sure that the image you want has the blue checkmark.
Step 4: Give your image a Title, Alt Text and Description
Note: I often use my blog post title in these sections
Step 5: Click on Set Featured Image

Step 6: Verify image shows up.
Note: You should only see the option to remove the featured image now.
Step 7: Save Draft

Conclusion
Your featured image is not only to have a nice and relevant image on your blog but it is also what generally gets shared on social media. This means that your image should represent your blog and your brand in a professional manner.
Suggested Reading:
18 Of The Best Tips On How To Compress An Image And Why
You always make things so easy to understand, Renee! What a great teacher you are, and I always appreciate your guidance!