Creating side by side images in a blog post
This article is for users who build post content in the WordPress Classic Editor environment. Follow the steps below to create a side by side gallery of images, also called a diptych.
1. First click the Add Media button. You can either upload two images or select two that you have already uploaded.
2. Then, click the Create Gallery link and click the Create a new gallery button to continue.
3. In the gallery settings, select link to: none, then change the columns to 2, and select the Full Size. Then, insert gallery! Your theme will take care of the rest.
See the steps above in the video below: