After countless try & error, here is the solution. The structure & format is remain the same as "bootanimation.zip" which will works if packed without compression (store compression level).
The only different is the way we zip as shown below.
# Running Linux :
* The correct zip command (im using latest Ubuntu on VirtualBox) is zip -0rD downanimation.zip <image folder> + desc.txt
# Running Windows :
* Windows using WinRAR :
1-Create zip like this
2- recreate the zip file but this time ignore file parameters in 2nd scrnshot.
3- open using winrar & delete all image files outside folder.