Issue with Transparent Background

[Fuction2005]

Hello 

I need help resolving an issue with the transparent background feature on my Shopify website.

I’ve developed a custom photo editor that enables customers to upload their images, which removes the background of the subject and saves the edited image as a PNG with a transparent background. This allows customers to customize and order their images as stickers.

However, when customers click "Add to Cart," the background of their uploaded image is supposed to remain transparent, matching the grey-and-white checkered pattern in the editor. Unfortunately, as shown in the attached image, the image background doesn’t display as transparent at checkout.

Here are my specific questions:

1. How can I ensure the image background stays transparent at checkout, matching the grey-and-white checkered pattern in the editor?
2. How can I make sure the image icon reflects this transparency, especially when customers click the Product API and image URL buttons?

Thank you!