Hello @swizzlevibes,
with images there are often problems with different email clients. It doesn’t seem to be specifically the case here but, for a broad solution, I suggest you upload your header image in “Google Fotos”, make the image public, then open it in google fotos, right click the image and then click “view image” or the equivalent in your language and browser, so that you get the full url. Then copy the url and paste it in the header image field.
This will make sure, that images are displayed in gmail for instance, which often blocks all kinds of images by their proxies.
Else the reasons could be ver specific to your hosting.
Where do you host the images?
Best regards
Julian
