512x512?

when you cloth youself the asset server send to you , and only you the textures that compose your avatar, from here, your client merge and resize all of them into 3 512x512 textures

low : base skin,tatoo,underpants,lower jacket,pants,socks,shoes
hi : base skin,undershirt,upper jacket,gloves,shirt
head: base skin, tatoo

from there your client re upload the 3 files to the SL server wich will broadcast it to all the other clients that can see you (if i remember its this)

it seems to keep for some time your clothes "collections" , like, if you wear a bra and a shirt , if you wear it again later, with nothing added it will load it instantly

the "outfit composite limit" seems to control how many "outfits" are saved that way, although I think only your outfits are saved... Not 100% sure, but it makes sense, and does seem to work with the little bit of testing I've done.

Thanks, so it's all client side issue.