2048 is just a hypothetical, i wanted to exaggerate

So help me understand, if I got it right:

So when you declare a non-null BMAP* in the script, the engine loads that image during the dots and puts it into memory, so when you run the effect, even with a 2048/huge image, the engine wont pause/stutter while the camera sees it for the first time. However the image is still loaded into memory correct? From the dots and onward, that image has been placed into memory, its area flagged as being used. Is there a way to purge this image later? What if I dont ever want the particle image used in a level? I would still have that area marked for usage in a level that wouldnt require that effect.

bmap_create on a BMAP* that was initially declared NULL, then fills that BMAP* with an image, as if you declared it regularly in the beginning. How does this help, besides saving memory in the beginning, before the image was filled with bmap_create? How will you remove that image from memory?