ILBM

Overview
ILBM (or IFF-ILBM, or LBM) is a raster image file format, based on the IFF container format. ILBM stands for InterLeaved BitMap.

Identification
The ASCII strings " ", " ", and " " appear near the beginning of the file.

Disambiguation
Apparently, "ILBM" is sometimes used as a catch-all term meaning "all IFF-based image formats". Or at least, the IFF-PBM (Planar BitMap) format is sometimes considered to be a kind of ILBM file. This is confusing, since Planar means the exact opposite of Interleaved.

If an image processing program claims to support ILBM, it's quite possible that it supports more IFF-based formats than just ILBM.

ILBM files are sometimes called "IFF" files, which is vague, but not incorrect.

Software

 * Netpbm
 * XnView

Sample files

 * ftp://ftp.back2roots.org/pub/amigascne/Gfx/pics/

Resources

 * Wikipedia article
 * ModdingWiki article