Image background keeps changing colour

If I upload an image, and set the design to ‘inline’ it is fine.

if I then change it to ‘poster’ or ‘card’ or any of the others, the colour of the background in the image changes to a pale yellow.

How do I stop this?

Thanks

You can change it in Design > Site Styles > Colors

Or if you share link to page where you added image, we can give simple code to remove this

Thanks - that's done it!