Of course you can batch import. First of all make sure you have named all your frames correctly. Assume you have created a unit animation that is called GoonRiveter. First you assign a name to all the animations (for example Idle, Walk, Attack, Hit, Death, Special). Then make sure you export your BMP files with the following name pattern:
<UnitName><AnimName>.<Direction>.<xxx>.bmpUnitName is your unit's name
AnimName is the name given to your animation
Direction is the direction your unit is facing (1 = S, 2 = SE, etc.)
xxx is the three.-digit index of the frame in the animation sequence, starting from 000
So for instance the second frame of the NW Death sequence will be GoonRiveterDeath.5.001.bmp
Easy, isn't it?
You need not make the background blue, the ILB importer will automatically recognize the transparency color you used for the background. In fact, purple is much more common as a background color.
Now to the import. Open ILBEdit and select Batch->New batch. Select the folder where you have all of your animations. Uncheck all general options except Indexed Files Only Type the name of your new ILB file in the File Name box. In the Script file box, select a text file with a .ILS extention that has the following contentsOffset=-101
Index1=100
Index2=1
Idle=01
Walk=21
Attack=41
Death=61
Hit=81
The first three lines are fixed, the following five tell ILBedit to look for the Idle, Walk, Attack, Death and Hit animations and place them in the ILB, for all six directions, starting from the position given (+00 for S, +100 for SE, etc.). In all my experiments, it took an index of 01 to tell ILBEdit to start at the 00 position. Hit the Run button, tell ILBEdit that you are doing a Multi selection, and: Lo and Behold! Your ILB is there.
Making new unit ILBs from 3D models is an activity that could make you very popular on this board