Hi ​@ellacoker ! 

Here are some recommendations for how to optimize your logo for dark mode inboxes. 

• Use logos and images that look great on light and dark backgrounds, like this one for Bola’s baked goods.
  

• Or add a light-colored shadow to a dark logo with a transparent background, so it stands out in dark mode.

• Alternatively, use image files that include background colors, rather than using a transparent background. If you choose this option, make sure your image completely fills the space it takes up (e.g., 600px wide for full-width images). This would be my recommendation for your use case! 

I hope this helps! :)