In Salesforce Marketing Cloud, after you add a text overlay on an image in the advanced tab, click apply and then click reset, the preview image may become larger. This breaks the layout of the content block. This is a known issue and will be fixed in a future version of the plugin.
You can use these work arounds in the meanwhile:
- After clicking 'Apply', navigate away from the 'Advanced' tab, say by clicking the 'Content' tab. You can then navigate back to the 'Advanced' tab and make any modifications to text overlays and click 'Apply'.
- OR navigate away and then back to the 'Advanced' tab. Click 'Reset' and then 'Apply' to bring the content block to its original state after which you can make your necessary changes.