FlashPix
FlashPix is a bitmapped computer graphics file format where the image is saved in more than one resolution. Though this makes it larger even than a TIFF file, when a request is sent for the file by a Web browser only the resolution required for the current screen resolution is returned to the browser; this therefore saves on bandwidth and download time.
History
FlashPix is based on the IVUE file format, the tiled/multi-resolution image file format that was used by the Live Picture software (Live Picture Inc).
In 1995, a consortium of Eastman Kodak (PhotoCD), Microsoft, Hewlett-Packard, and Live Picture Inc were looking for a powerful image file solution, and Live Picture's solution was the best approach for handling large image files.
Technical Overview
FlashPix files have the .fpx file extension. FlashPix uses Microsoft's structured storage format which stores hierarchical data in a single file.
Each image is stored with its sub-resolutions. Each resolution is divided by 2, until the entire image can fit in a single tile. Tile size is variable, but the default usage is to have 64 x 64 pixel tiles (IVUE was using 256 x 256 pixels). Each tile can be compressed independently of other tiles using various algorithms (LZH, JPEG, RLE). Each pixel can have any number of channels of any size (for instance a 16 bits CMYK image), interleaved or not. Including Alpha channel.
