Board (legacy text-to-image product)
Images created on Board are generated publicly by default. However, if you are a paid user, you can generate private images by clicking on the slider under Private Session.
For legacy Free plans, this setting does not persist between page loads, so when a page is refreshed, you'll need to select it again. Otherwise, this setting does persist for Pro subscribers.
To make a previously created image either private or public:
Select "My creations" after clicking on your avatar:
This will display a section entitled "My Images" with a gallery of all your previously created images.
Click on "Select Images" and then choose the image(s) in your gallery that you want to make private or public by clicking on them.
You can bulk select all images in between two given images by clicking on the first image and then clicking Shift+click on the second image.
Select the ellipses (...) and then click "Make Private" or "Make Public," as desired.