Preview images

Status

Field	Value
Extension(s)	.bmp, .png, .jpg
Common ecosystem	Machine previews and design bundles
Format family	Sidecar or embedded metadata
Satin Studio status	Researching
Open / import	No
Export	No
Confidence	High for preview role.

What it is

Preview images may be embedded in machine files or shipped beside them to show the design visually.

Satin Studio direction

Preserve or regenerate previews as metadata; do not treat preview images as source geometry.

Versions and variants

Preview image sidecars use ordinary image formats, but embedded previews inside machine files are format- and version-specific.

File identification notes

Standard image formats or embedded bitmap sections.

Observed structure notes

• Sidecar previews are ordinary image files. PNG begins with 89 50 4E 47 0D 0A 1A 0A; JPEG begins with FF D8; BMP begins with BM plus a file/DIB header.
• Embedded previews must be located by the surrounding machine-file parser before ordinary image parsing applies.
• Embedded machine preview images may be raw bitplanes or palette-indexed graphics instead of standalone PNG/JPEG/BMP files. The surrounding machine format must define width, height, stride, and palette before display.

Structure sketch

Preview images are ordinary image formats when stored as sidecars and format-specific blobs when embedded.

enum PreviewImage<'a> {
    Png { signature: [u8; 8], chunks: &'a [u8] },      // 89 50 4E 47 0D 0A 1A 0A
    Jpeg { soi: [u8; 2], segments: &'a [u8] },         // FF D8 ... FF D9
    Bmp { file_header: [u8; 14], dib_header: &'a [u8], pixels: &'a [u8] },
    EmbeddedFormatSpecific { payload: &'a [u8] },
}

What we still need

Per-format preview behavior and export package design.