File size in bytes.
OptionalheightIntrinsic height in px.
MIME type, e.g. 'image/svg+xml', 'image/png', 'image/webp', 'image/jpeg'.
OptionalsvgRaw SVG markup (when the upload is an SVG) — enables single-fill detection.
OptionalwidthIntrinsic width in px (raster pixels, or the SVG viewBox/width).
File facts the caller extracts (byte length, mime, intrinsic size, SVG source).