I'd have to see the images in question -- but with since they're illustrator that usually means low color depth, meaning if you want to get them smaller go to 8 bits (256 colors) or less in PNG and see what happens. Manually trimming white-space can also have an effect though to be honest...
1000x288 treads into what I like to call "Not viable for web deployment" -- and while you see people sleazing out websites with images that large on them, the filesize alone of anything that large would be bigger than the upper limit I usually allow for an entire PAGE on a site; that's images+css+html+scripts.
Though again, I'd have to see the image in question before weighing in on it -- but if it's 60 megs as a illustrator (vector) image, I almost dread to see it as the only justification for that LOD is details that wouldn't even RENDER at only 1000x288. (you sure it's not 4.1"x2" stack-card size designed at 144dpi, meant for 1200dpi print?)
When the size of a vector file is 54 times what it would be as a 32 bit unencoded bitmap, something's screwy.