Navigate to Campaigns > Templates Manager > Create Template
There are two ways to upload your logo image:
1) To upload your Logo Image please click the "Upload" button
If you upload your Logo Image, use the variable [[LOGO_IMAGE]] inside your template so it will be displayed inside your email template. Keep in mind the variable is NOT resizable.
2) If you want to resize your logo image, instead upload the logo as a picture with the picture icon:
A pop up will appear to insert image:
You are able to insert the image or simply copy/paste the logo image directly into the template.
In order to resize the image, simply click the image and the sizing options will appear
OR you can also drag the image from the bottom right corner in order to resize it: