GD image format

File Format
Name	GD image format
Ontology	Electronic File Formats Graphics GD image format
Extension(s)	.gd
Released	~1994

GD image format is a raster graphics file format associated with the GD graphics library (a.k.a. LibGD), originally developed by Thomas Boutell.

The GD image format is a special purpose format that can be read very quickly. It is not GD's preferred format -- standard formats like GIF and PNG are preferred.

There are several versions of GD format.

See also GD2 image format.

Identification

GD 1.x: There's no easy way to identify this format version.

GD 2.x palette color: Starts with bytes 0xff 0xff, and has 0x00 at offset 6.

GD 2.x truecolor: Starts with bytes 0xff 0xff (v2.0.0-2.0.11) or 0xff 0xfe (v2.0.12+), and has 0x01 at offset 6.

Specifications

• Refer to the source code comments in modern versions of the gd_gd.c file.

Software

• GD/LibGD
  • GD 1.2, from the Wayback Machine
  • https://ftp.mizar.org/packages/gd/ - Various versions
  • See the LibGD website for the latest release.
  • LibGD GitHub project

Links

• LibGD website
• [https://libgd.github.io/manuals/2.3.0/files/gd_gd-c.html LibGD website format info