Function replace 

pub fn replace(
    project: &str,
    id: i32,
    extension: &str,
    content: &[u8],
) -> Result<ImageSummary>

Replace an image’s bytes, keeping its id, so everything that uses it shows the new image. The extension is jpg, jpeg, png, webp, or svg, and must match the image.

Needs image.replace or content:write in the manifest’s [permissions].