When you upload an image, it is aligned to the left by default. You can center the image or align it to the right using either the image toolbar or the align property in markdown to position the image correspondingly.
From the editor, once an image is selected the image toolbar appears, where you can select one of the three alignment options: Align left, Align center and Align right.
While writing in markdown, you can make use of the align property:
Aligning an image to the left
// Markdown
![alt text](myAwesomeImage.png align="left")
Aligning an image to the center
// Markdown
![alt text](myAwesomeImage.png align="center")
Aligning an image to the right
// Markdown
![alt text](myAwesomeImage.png align="right")