Slice 2D transparent image with multiple elements inside

Hello! I am creating some sort of runtime generator, and I have one specific problem:

For a given image in input (a png like that), I would like to be able to separate the shape inside the it, to get the number of individual element I can find (here it would find 15 different element).

Then, I would like to be able do display or hide each element separatly (maybe just create an png image as output, with just X elements (like the image bellow).

What would be my approach to this ?

Thanks!