ILBM/IFF files

ILBM files (InterLeaved BitMap) are used to store all interface graphics in UA. They have different filename extensions:

ILB is used for interface object and icons. Note that definition files may contain references to “ilbm” although they point to “ilb” files.

IFF is used for background images, level masks and so on.

It should be noted that ilbm extension is also used for VBMP files which are mostly stored inside BAS files. These are NOT ILBM files, they are special bitmaps which resemble ordinary bitmap files (BMP), having custom headers, pre-defined color map stored elsewhere and being usually created upside-down. Editing these files requires special procedures.

File locations

Unit icons, map graphics, interface objects, in-game text etc.
See Unit icons for a list of files and examples.

Mouse pointers

Interface-related

\<leveldir>\mbpix\
\<mbpix-dir>\
Mission briefing maps

\<leveldir>\bg\
Menu and briefing backgrounds, level selection screen etc.

Explosions and effects

Editing tools

Ultimate Paint can edit ILBM files natively but it may have problems with the color palette.

XnView can open and convert ILBM files into other formats.

IrfanView should also be able to open ILBM files but may require additional plugins.

Notes

ILBM files support RLE compression but it's not known if UA supports it as well. It's recommended to save them without compression.

Level selection masks (e.g. MASKE.iff) use color indices as level identifiers and it's thus important to use correct color palettes. »additional information needed!« If you get a program that can edit the color palette, the order of the colors determines the order of the levels to be unlocked.