This is an attempt to explain how to I am using as an example an on-shelf filmstrip for a clothing item which someone sent to me for help.  The numbers in your filmstrip will be different of course. 

1 ) put the filmstrip in Axe and have it so that it looks right.  Select the whole area.  Make a note of the numbers at the bottom where you see Sel: (the number 2c4c is what you note down) and Row: (6c is the number)

2 ) now get the bitmap header from my tutorial zip.  Open it and the filmstrip into a hex editor of your choice.  I use Hex Workshop.  Select the whole of the bitmap header and paste it into the beginning of the filmstrip

3 ) save.  Now you need to change some numbers in the header.  Select the whole of the file and note the number at the bottom of the editor, where it tells you how much you've selected (it needs to be set to show numbers as hex).  It's 3080.

4 ) now go to the top of the file and replace F20B with 8030 (you reverse the 3080, don't ask why, you just do). 

5 ) go back to the numbers you noted down before.  2C4C is the size of the filmstrip in hexadecimal.  Go to the BC07 in the header and replace it with 4C2C.  Go to the 14 that's in the line above and replace it with 6C.

6 ) now open Windows' calculator and make sure it's set to View Scientific.  hit the radio button beside hex and enter 2C4C, then the divide sign ( / ), then 6C, then the = sign.

7 )  back to the hex editor.  In the line where you entered the 6C, you'll see 63.  Replace that with 69

8 ) save. Now you can open it in a paint package, edit it, save it, and then strip off the bitmap header and pop it back into the clothes item as mentioned in my tutorials.