Need advice on uploading photo for print.

[kyutip]

I need help fast. my ofoto credits are expiring in a couple days.
I just got some picture from my DC4800.
I've never upload photo for print before.
My question is which type of file that I should upload ? (3.1MP)
the untouch jpeg (huge file) or use photoshop to keep the resolution but reduce the file size ?
If I do reduce it, will it reduce the print quality ? (4X6 print)
any help would be really appreciated.
thanks

 

[pdo]

try converting TIFF into highest quality JPEG then uploading it to OFOTO.