Image formats

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The following is a list of common file formats used for images in DRAW Your Own Story with information on their strengths and weaknesses.

Bitmap

A bitmap (.bmp) or pixmap is a memory storage scheme that maps pixel colour values to bits. The BMP file format was established by Microsoft as a standardized scheme to allow inter-device display. Uncompressed bitmaps can display rich colour depth but at exorbitant file size; CivFanatics allows BMP attachments but not hotlinking, and most online image hosting services will convert bitmaps to a more compact format during upload. Thus, bitmaps are useful as 'master versions', but not as 'export versions'.

JPEG

Universal standardized image format created by the Joint Photographic Experts Group for ISO TC97 WG8 and CCITT SGVIII (today ISO/IEC JTC1 and ITU-T), commonly affixed .jpeg or .jpg. JPEG reduces file size by normalizing frequency data, although this can result in lossy compression, especially if the image is re-saved multiple times:

Lossless JPEGs are possible, but most basic image editing software such as Microsoft Paint do not provide quality controls; complex editors such as Photoshop and GIMP do. JPEGs are generally more size-efficient than PNGs at storing true-colour photographs and high-detailed illustrations. JPEGs can also be saved in an interlaced format that will progressively render a display from low to high detail, useful for general previews on slower Internet connections.

Graphics Interchange Format

Graphics Interchange Format (.gif; officially pronounced /ˈdʒɪf/, commonly /ˈɡɪf/) is a file format introduced by CompuServe popularly used for animated images. GIF uses a lossless compression algorithm but requires the image to use a 256-colour palette index. It is roughly comparable to PNG and JPEG in terms of file size, and can support transparent backgrounds.

Portable Network Graphics

Created out of a licensing dispute over GIF, Portable Network Graphics (.png) is a lossless compression algorithm and a successor of sorts to GIF. PNG can render true-colour images and transparent backgrounds; an animated extension (APNG) exists, but is not well-recognized. PNG is generally superior to JPEG regarding images with small dimensions and/or simple colour schemes, but photo/dynamic-colour images tend to produce larger file sizes.

Scalable Vector Graphics

Scalable Vector Graphics (.svg) is an open standard, XML-based image format, and as such, can be edited through a text interpreter as well as dedicated image software. SVG defines an image through sets of shapes, and can therefore both downscale and upscale a file without pixelization. SVG is recognized in most modern browsers, but is not widely supported by image hosting services, and so like bitmaps is best used as a 'master copy'.