The best way is in PDF format. If you have a PDF but it is over 10mb then you can still make it high-quality but much much smaller.
Heres what you can do.
Take your .psd file (the one your working with) or .pdf - whichever (the big fat momma one)
SAVE AS (yourinsertname.jpg)
- it will prompt you for quality - select 12, Maximum.
once you have done that, open up the JPG file that you just saved as and do yet again:
SAVE AS (yourinsertname.pdf) <- now your making another PDF so be sure not to name it the same as your original.
It will prompt you again for quality and this time select 10, Maximum.
The result should be a PDF file that is equal in quality (at least to the average human being) but 10times smaller!
try it out see what happens.
once you have your final PDF file, break it up into 1mb chunks using winrar. You shouldn't end up with more than 3-4 files.
Most of the files on Kazuyas are inflated big-time and the users didnt really take advantage of compression techniques. Just because your inserts are less files will not make them any less-quality than the others on the site.
Good Luck,
NeoCverA