How can I set a product metafield to be a file reference (image) using graphQL?

Retired Boards Appdev Graphql Basics And Troubleshooting
1

How to get from here to there?

I have a few images that I need to attach to a product but not be visible as product image. I would like to use a metafield with the type file_reference. I see how to read it out, but not how to set it. As I understand, I need the mediaImage id to set its value. I can do a staged upload but how do I get from there to a gid for the image?

It should be going into something like this …

Thanks! and best regards jb

metafield(namespace: “xxx”, key: “yyy”) {
reference {
… on MediaImage {
image {
originalSrc
}
}
}
}