Image formats
This is an essay.
It contains the advice or opinions of one or more of the Valve Developer Community's contributors.
This page is not an encyclopedia article, nor is it one of the Valve Developer Community's policies or guidelines, as it has not been thoroughly vetted by the community.
Some essays represent widespread norms; others only represent minority viewpoints.
It contains the advice or opinions of one or more of the Valve Developer Community's contributors.
This page is not an encyclopedia article, nor is it one of the Valve Developer Community's policies or guidelines, as it has not been thoroughly vetted by the community.
Some essays represent widespread norms; others only represent minority viewpoints.
…
The following is a list of standard image formats, along with which engines support them, whether they are compressed, and when I recommend using them.
Important:These are subjective recomendations; do not move the page out of userspace! Instead, consider copying the objective segments to a new page.
Warning:I have not personally tested the any formats in 
or 
, as I don't have either available to test. I also have not tested IA88, A8, or BGRA16F. The information stated on this page regarding those is based upon conceptual knowledge of the formats and preexisting documentation regarding strata's VTF v7.6 and Source 2's VTEX formats.| Supported in | ||||||
|---|---|---|---|---|---|---|
| Format |  GoldSrc |
 Source |
Strata |
Source 2 |
Compressed? | Recommended usage |
| P8 (256-color) | Yes, except for main menu backgrounds and detail textures | No (use BGR565 or BGRA8888) | No (use BC7) | No (use BC7) | Yes, 1 palette for entire image with 256 colors | : Most textures (world, models, sprites, overviews, etc.)
|
| BGR888, RGB888 (24-bit true color) | Limited; only for skyboxes, detail textures, main menu backgrounds, and VGUI elements | Yes | Yes | Yes | No (except in , see notes)
|
: Skyboxes, detail textures, main menu backgrounds, and VGUI elements
|
| BGRA8888, RGBA8888 (32-bit true color with translucency) | Limited; only for VGUI elements | Yes | Yes | Yes | No | : Densely detailed textures with alpha channels
|
| BGRA8888, RGBA8888 (Source 1 Compressed HDR, aka "RGBM"; sky shaders only) | No | Yes | Yes | Yes | Yes; alpha channel used as a multiplicand rather than for translucency (see Valve Texture Format#HDR compression) Can also be combined used with DXT5, but doing so is not recommended. |
: HDR skyboxes
|
| BGRA16161616F, RGBA16161616F (16 bpc Floating Point HDR with translucency) | No | Yes | Yes | Yes | No | , , : HDR textures with an alpha channel
|
| BGR565 (16-bit color) | No | Yes | Yes | No (use BC7) | No | : Low-res normal maps without specular mask;
|
| BGRA4444 (16-bit color with translucency) | No | Yes | Yes | No (use BC7) | No | : Not recommended; causes noticable color shift rendering it unable to convincingly portray a flat normal map.
|
| I8 (8-bit greyscale) | Technically (using P8) | Yes | Yes | Yes | No | : Specular masks for materials without a normal map (avoids DXTn green tint; same file size as DTX5).
|
| IA88 (8-bit greyscale with translucency) | No | Yes | Yes | Yes | No | : Greyscale decals with an alpha channel
|
| A8 (Translucency only) | Technically, only for sprites (using IndexAlpha) and decals | Yes | Yes | Yes | No | , , & : Single-color textures with an alpha channel (use material coloring to assign non-white colors)
|
| DXT1 (AKA BC1) | (only in  )
|
Yes | Yes | Yes | Yes; two explicit BGR565 colors and two interpolated colors per 4x4 block | , , & : Moderately detailed high-res textures with no alpha channel
|
| DXT3 (AKA BC2) | No | Yes | Yes | No (use DXT5) | RGB only; RGB handled like DXT1, with uncompressed 4-bit alpha | , : Not recommended, use DXT5 instead
|
| DXT5 (AKA BC3) | No | Yes | Yes | Yes | Yes; RGB handled like DXT1, with alpha handled like ATI1N | , , & : Moderately detailed high-res textures with an alpha channel
|
| ATI1N (AKA BC4) | No | No (use I8) | Yes | Yes | Yes; four explicit I8 values and four interpolated values per 4x4 block | : Specular masks for materials without a normal map.
|
| ATI2N (AKA BC5) | No | No (use BGR565 if really necessary) | Yes | Yes | Yes; two independent ATI1N-style channels (red and green) | : $blendmodulatetexture, perhaps
|
| BC6H (AKA BC6) | No | No (use compressed BGRA8888) | Yes | Yes | Yes; four explicit RGB161616 or RGB161616F colors and four interpolated colors per 4x4 block | & : HDR skyboxes
|
| BC7 | No | No (use BGR565 or BGRA8888) | Yes | Yes | Yes; four explicit RGB888 or RGBA8888 colors and four interpolated colors per 4x4 block | & : Whenever DXT1 or DXT5 is too blocky and/or DXT green tint needs to be avoided.
|
Note:The Steam versions of support RLE-compressed TGA files for certain use cases, such as skyboxes and detail textures. Other use cases, such as taskbar icons or transparent VGUI sprites, do not support RLE compression.Not all programs can export compressed TGAs; GIMP does this when exporting to TGA by default. Make sure that the origin is set to "bottom-left".
Note:All formats supported by can be compressed with PNG-style deflate compression, using its custom v7.6 VTF format. This is used in conjunction with whatever inherent GPU-supported compression format is being used; as such, it is not mentioned in this table.Note:Although the VTF format used by supports encoding color channels in multiple orders (RGB, BGR, RGBA, BGRA, ARGB, ABGR), only BGR and BGRA are guaranteed to work correctly. By comparison, prefers RGB and RGBA, using its VTEX format.
Note:Additionally, formats with a 1-bit alpha channel, such as BGRA5551 or BGR888_BLUESCREEN are not as reliable as those with a 4-bit or 8-bit alpha channel, and will often treat the entire image as opaque, with the transparent pixels appearing as black.Formats with 1-bit alpha should be avoided anyway (except in
), even when using $alphatest, as it will result in inaccurate transparency on mipmaps.Note:, , and all support non-floating point HDR textures, however floating point is preferred, as it allows for better precision over the texture's brightness. VTEX defaults to floating point when using nocompress with pfm (see HDR Skybox Creation#Creating the Materials).