.blk file extension

I'm wondering if anyone is familiar with a older-type graphics program
that opens files with a .blk file extension. I'm trying to edit image
files that were created for an LED moving message machine that others
have indicated might have been made on an Amiga computer 10 or so years
ago. If someone would send me email, I'll send one of the files to you
and you can see if it can be opened in whatever image editing programs
you have. I know zip about Amigas (sorry guys...), but it seems like
the Amiga is probably the most likely type of program to open these
basic one-three color images. The only info I can find on the net about
blk file types is:

..blk file extension, .blk file type - Alias Wavefront Image file
..blk file extension, .blk file type - Amiga IFF ILBM image
..blk file extension, .blk file type - Lightscape Block Library file
..blk file extension, .blk file type - WordPerfect tem****ary file

I doubt that these were created in WordPerfect, but it's not
impossible. I have no clue what Alias and Lightscape Block type files
are, except that "lightscape" sounds interesting.... From what I've
gleaned in the last few minutes, it's a graphics program used by
architects.

Does anyone have a clue as to whether a .blk image file could be a
format formerly used in an Amiga paint-type program. The files would
have to be limited to one, two or three color since the moving message
board can only display three shades of red.

Finally, it should be mentioned that there are also .zbk files in this
same BLK directory. I had made an assumtion that these were files that
were also graphics renamed so that the program I'm working with
(JVFF.exe) wouldn't open them... if that makes sense (I often rename an
extension so it won't open by its registered program)

Anyway, that's my problem. Does any of it sound familiar?? Can anyone
help. Thanks in advance, if you can!

Joe