To get started adding images to your email templates you can head to the Email Templates page, this is found by navigating to Marketing » Email » Email Templates.
From there, you can create a New Custom Template or edit an existing template (click on the name of an existing template).
To add an image to your template, simply click on the template wherever you would like an image to be placed, then click the Insert/Edit Image button.
Next, either click the Upload link to upload your image (or click the Upload Icon), or paste in the URL of an image hosted someplace online.
Once the image has been uploaded, or linked to, you can click on the image within the template to make edits such as cropping, rotating, resizing, and brightness and contrast changes.
If you would like to use that new template as a Bulk Email you can head to Marketing > Email > Bulk Email. From there click on the Start From a Template box at the top and choose your template.
You can also view our article on How do I create an email template? if you need further help.