The GIMP IFF plugin allows you to load and save .iff/.lbm pictures. It supports 1-8, 24bit planar images, 3-8bit HAM and EHB images, 12/24bit Imagine/TurboSilver pictures and DPaint IIe output. It saves indexed, grayscale and 24bit. Compression is supported, as well as transparency (masks) in most cases.
