Currently, you are not able to wrap text around an Image Element. That said, there is a workaround you can use to make it look as though your text is wrapped inside your Blast when opening on desktop.
How To Create the Workaround
Follow the steps below to learn how to make your text look like it’s wrapped around an image:
Go to Blast > Create New to open the Blast Editor for a new Blast.
Click and drag an Image Element into the Blast Editor > add your image.
Click and drag a Text Element into the Blast Editor, and place it next to the existing Image Element, and add the beginning part of your text.
If you need help dragging and dropping Elements in your Blast, check out this article.
Click and drag another Text Element into the Blast Editor, and add it UNDER the existing Image Element, and add your text.
Inside the Layout tab of each Text Element, change Top/Bottom margin (located under Container Style) to 0.
If necessary, adjust the Image Element.
To adjust the width:
Hover your cursor over the Left Element (when you are not currently editing an element), and you will see a blue line appear with three dots. Click and drag the three dots right or left to alter the Image Element width to your liking.
To adjust the Image Size:
Click on the Image Element, and inside the Layout tab, you can manually adjust the Image Width percent.
Click Keep and Save as Draft when ready.