The image assigned in your Admin area under the Site Logo field is used for the header logo and navigation logo. 

You can type in the name of a media file you have previously uploaded, or you can upload a new image and it will save the logo in your media files.

The logo will be capped at a width of 240px.

We recommend using a PNG file for the logo. A PNG file supports transparency in the image, specifically transparent backgrounds. Transparency allows you to see the logo image while also seeing the background of the website page behind it.

JPG, BMP, or GIF files may also be used, but these file formats do not allow for transparent backgrounds. You'll see the full background shape of your logo image without transparency.