Changing out the Logo
WordPress can crop, re-size and proportion your logo image for you. Alternatively, you can edit your logo file in a graphix program and set the initial size to 120px x 120px.
The Theme Customizer will appear, click on to enter the Media Library. If your logo is not yet in the library, use the tab to get to the file uploader. Once you select your logo in the media library, you will get to the cropping page. If your logo fit perfectly in the crop box, you can skip cropping, otherwise, move the edges of teh cropping tool to outline yur entire logo, then crop.
If you are really good a graphics and if your logo is monochrome, your logo will look better if you set the color to hexadecimal #1A2B43.
The background of the logo should be transparent or white (#FFFFFF)
If you don’t have a logo, you can blank out the default logo with this blank white image in the media library: