The Text and Image Block allows you to combine text over images. 

To add a Text & Image block, go to Block > Add > Text & Image

Once this has been selected, the Text & Image block editor will appear

Text Tab

The text editor is similar to your Text Block. To change the text alignment, use the nine small boxes in the lower left corner.

To change the width and padding, use the sliders in the Text tab.

To change the text box background, use the colour slider below the editor. You can also change the opacity of the background.

Image Tab

To select an image, go to the Image Tab and click on 'Select Image'. Your Image Library will appear.

To change the image alignment, click on the nine small icons on the right of the image tab.

To change the image background colour, go to the colour picker. You can also change the opacity.

Settings Tab

Click on settings to find the Height adjustment, Linking to a page, Mobile Text Reduction and more.

 To change the height of the banner, go to the Settings tab and adjust the height.

Select save and you're good to go!