Feature Image bottom margin

Hello,
I installed your plugin as my customer would like to have an RSS to mailchimp newsletter set up.

It all works fine, the only thing that doesn’t work is the margin at the bottom of the image. I set it in the plugin but it doesn’t seem to take it.

I also tried adding it to the newsletter template via css but it still doesn’t add a margin on some devices.

Is there any other way I can control this?

I tried inserting the feature image and excerpt separately but that didn’t work either but more in the sense that the image did not come through.

Thanks, heaps, appreciate your help.
Kindest Regards,
Corina

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