ILBM File

What are ILBM files and how to open them

Are you having problems opening an ILBM file or are you simply curious about its contents? We're here to explain the properties of these files and provide you with software that can open or handle your ILBM files.

What is an ILBM file?

ILBM files have multiple uses, and IFF InterLeaved BitMap is one of them. Read more about the other uses further down the page.

IFF InterLeaved BitMap

IFF InterLeaved BitMap (ILBM) is an image file format used primarily on Commodore Amiga systems for storing bitmap graphics. It is based on the EA IFF-85 standard and packages image pixel data, palette (color map), and display metadata in a structured chunked file. It is most often produced by Amiga-based graphics tools and used to save or exchange colored images in modes Amiga supported.

Producers write ILBM files by creating an IFF FORM of type "ILBM" (or sometimes "LBM") that includes several chunks: a mandatory bitmap header (BMHD) specifying image width, height, number of bitplanes, displacement origin, compression style, and aspect ratio; optional chunks such as a color map (CMAP), display mode flags (CAMG), transparent color or masking; and the BODY chunk holding the actual image pixel data encoded in interleaved bitplanes, optionally with simple run-length compression. Readers parse the header and color information first, then interpret the BODY data to reconstruct the image.

Files start with the ASCII signature FORM at offset zero, followed by the "ILBM" identifier at offset eight. The signature uniquely identifies the file as a FORM ILBM image.

How to open ILBM files

We have identified one ILBM opener that is compatible with this specific type of ILBM file.

Programs that open IFF InterLeaved BitMap files

Last updated: August 7, 2026

All known file formats using extension .ILBM

While IFF InterLeaved BitMap is a popular type of ILBM-file, we know of 4 different uses of the .ILBM file extension. Different software may use files with the same extension for different types of data.

IFF Newtek Dynamic HAM Bitmap

We know that one ILBM format is IFF Newtek Dynamic HAM Bitmap. We have not yet analyzed in detail what these files contain and what they are used for. We're working on it.

While we have not verified the apps ourselves yet, our users have suggested six different ILBM openers which you will find listed below.

IFF Palette Changes HAM BitMap

We know that one ILBM format is IFF Palette Changes HAM BitMap. We have not yet analyzed in detail what these files contain and what they are used for. We're working on it.

IFF Sliced HAM Bitmap

We know that one ILBM format is IFF Sliced HAM Bitmap. We have not yet analyzed in detail what these files contain and what they are used for. We're working on it.

Various apps that use files with this extension

These apps are known to open certain types of ILBM files. Remember, different programs may use ILBM files for different purposes, so you may need to try out a few of them to be able to open your specific file.

Help us help others

File.org helps thousands of users every day, and we would love to hear from you if you have additional information about ILBM file formats, example files, or compatible programs. Please use the links below or email us at submit@file.org to discuss further.