Microsoft Bitmap (.bmp, .dib, .rle)

The Windows bitmap file format is the standard file format used by Microsoft Paint (Windows Paint program), and is also supported by a number of DOS applications. Bitmap files can contain either 2 (black and white), 16, 256, or 16.7 million colors. Most Windows bitmap files are not compressed, although it is possible to save 16- and 256-color images in a compressed format using run-length encoding (RLE), but some applications (notably Windows Paintbrush) are not able to read the compressed files. The RLE compression is a lossless compression scheme, meaning that the image quality is not compromised.

Generally, you do not use this format when creating textures, but you may encounter this when searching for reference. Use this format when saving images that you wish to use as wallpaper images in Windows.

Most bitmap images have the .bmp extension, although you may occasionally encounter some with the .dib (device-independent bitmap) extension, which are sometimes used in computer multimedia systems.

Encapsulated PostScript (.eps)

The encapsulated PostScript format is purely an interapplication format to allow files to be traded from one software application to another with ease. This includes programs such as QuarkXPress, Adobe Illustrator, Corel-DRAW, and many other graphics and graphics-related software packages. This format is specifically designed to save object-oriented graphics, such as you would find in any vector-based drawing program, intended for printing to a PostScript device. What it does is rasterize the vector shapes to create bitmap images for transfer.

LightWave is able to export different viewports from Modeler into EPS files, which is useful for exporting UV maps and such for use in other programs like Adobe Photoshop.

CompuServe Graphics Interchange Format (.gif)

Never used in creating textures, the GIF format is primarily for images that require a small file size for exchange over modems (which is what it was originally designed for), and obviously for uploading onto the web. This format uses LZW compression (Lempel-Ziv-Welch, the same compression scheme as TIFF), but is further optimized by limiting the image to a maximum of 256 colors.

There are two types of GIF, each of which utilize a slightly different codec. The first type is GIF87a, which supports only opaque pixels. The second type, GIF89a, allows transparency via an alpha channel.

Radiance High Dynamic Range Images (.hdr, .hdri, .pic)

A relatively new image format, HDR images have the ability to contain information that is beyond the range of other file formats. These images can be used as sources of illumination within 3D scenes, and are usually in the form of light probe images, which are compiled photographs taken of chrome spheres that reflect a 360º environment.

Amiga Interchange File Format (.iff)

You may well encounter programs that still (often accidentally) produce IFF files (IFF is Maya’s native render format, actually), but generally you do not actually work with them. This format was the common graphics format for Commodore’s Amiga computers, which are no longer really used.

Programs like Adobe Photoshop allow you to open and save IFF files, as do some older programs like Electronic Arts DeluxePaint. If you encounter these files, you should save them in a different format, as many applications are unable to read them. Some UV mapping plug-ins, especially the slightly older ones, export the UV maps to IFF files by default.

Joint Photographic Experts Group (.jpg, .jpeg)

Possibly the most widely used graphic file format on the web and in the office, JPEG is one of the most efficient and versatile compression formats currently available for images.

One thing to be aware of is that the JPEG format uses a lossy compression scheme, which means that it sacrifices image quality in order to decrease file size. Thus, when saving textures in this format, it is best to leave the quality on maximum to avoid a loss of quality. The advantage to using JPEG is that the file sizes of the textures are considerably smaller than TGA or TIFF formats, thereby reducing rendering time.

The JPEG format is a great choice for images that you wish to upload to the web, as you can compress the images quite substantially without a devastating loss of quality.

Too much compression, however, results in the image becoming very blocky. It is not recommended for images with high contrast or line drawings, as these tend to lose a lot of their definition.

JPEG can be a useful format for saving renders; however, since the file format does not support alpha channels, you lose that information. If you are saving the render so that you can upload it to the web, then this is a good choice. Use a program such as Adobe Photoshop or any other decent image application to adjust the amount of compression on the image.

Apple Macintosh Picture (.pict, .pct)

Just as Microsoft Windows has its native BMP format, the Macintosh platform has the PICT (Macintosh Picture) image format. PICT is an extremely versatile format, as it can handle both vector and bitmapped images, and also supports 32-bit image depth, meaning that it can contain alpha channels.

Although this format is a great choice for a number of different uses for Mac users, it is not really ideal for PC users, and TGA and JPEG formats can be used instead.

Portable Network Graphics (.png)

Pronounced ping, the PNG format has been until recently primarily a web-oriented image format that enables you to save images in 16 million color without compression quality loss. Another benefit of this format over JPEG, for example, is its ability to contain alpha channel data. Even though PNG has its origins in web graphics, it has been steadily gaining popularity in the CG industry with some studios switching to this format exclusively mostly due to its lossless color compression efficiency.

Tagged Image File Format (.tif, .tiff)

Originally developed by Aldus in the early days of the Macintosh, the TIFF format is still one of the most widely used image formats in the printing industry, especially since it is compatible with both PC and Mac platforms. TIFF files can be imported and exported by most 2D and 3D applications.

It is a good choice for saving renders that are intended for the print medium, but not really a useful choice for texture maps.

You can optionally compress TIFF images using the LZW (Lempel-Ziv-Welch) compression scheme, which is a lossless compression. LZW compresses the file size to about half of the uncompressed size without any loss of image quality.

Truevision Targa (.tga)

The best choice for rendering image sequences intended for compositing and broadcast, the TGA format offers 16-bit, 24-bit, and 32-bit images, the latter including alpha channels.

Targa files are uncompressed, which means that their file sizes are rather large, but their quality is perfect, making them an ideal choice for renders and images.

Texture maps that require alpha channels can be saved as 32-bit TGA files, which include the alpha, thus preventing you from having to create a separate image to act as the alpha when the texture is applied to the model.