Thank you for reaching out to the Community! You can definitely share an image from your email campaign. This can be done by downloading your desired image through the image URL from the Library tab of your account.
From the Library, click the Edit icon to the right of the image you want to use.
This will give you a pop up of your image where you can click "copy" to access the full URL.
Once you have done this, enter this URL into a new tab or window of your browser, and download your image from this page.