Function write_slice_png 

pub fn write_slice_png(
    path: &Path,
    raster: &RgbImage,
    palette: &Palette,
    limits: (f64, f64),
    scale: ScaleMode,
    variable: &str,
    units: Option<&str>,
    long_name: Option<&str>,
    standard_name: Option<&str>,
    time_label: Option<&str>,
    depth_index: usize,
) -> Result<(), Box<dyn Error>>

Write a slide-compatible PNG containing the map, a colorbar, and tick marks. The SVG companion remains the annotated/editable export; this raster format is intended for direct insertion into Google Slides, PowerPoint, reports, and notebooks that do not preserve SVG text/layout.