JetBlue TrueBlue - Checked Baggage sizes

I am traveling form JFK/New York to Cancun in a few weeks and want to bring a painting with me. It is boxed and doesn't weigh more than 50 lbs. What are the sizes of boxes that
I can bring...and how do I figure it. Can I pay extra if it is over sized.
thanks

From jetBlue's help section: (http://help.jetblue.com/SRVS/CGI-BIN/webisapi.dll/,/?St=76,E=0000000000015217217,K=357,Sxi=12,Case=obj (634))

Aruba, Bahamas, Bermuda and Mexico
Free Baggage Allowance

You may bring two bags per person free of charge.
Each bag must NOT exceed 62 inches in overall dimensions (length plus width
plus height) and can NOT exceed 50 pounds.

Excess, Overweight and Oversized Baggage

Excess bags will be accepted for a fee of $80 per bag on a load availability
basis.

Overweight or oversized baggage may be checked on a load availability basis
per the guidelines below:

Overweight Bags:
51 - 70 pounds: $20 per bag
71 - 99 pounds: $80 per bag
Bags over 99 pounds are NOT accepted.

Oversized bags:
63 - 80 inches: $80 per bag
Bags over 80 inches are NOT acccepted.

Boxes are NOT accepted.

Checking in Your Bags

All baggage must be checked at the airport at least 60 minutes prior to flight
departure
Baggage will NOT be accepted for check in more than four hours prior to a
flight's scheduled departure time


Unfortunatly, it looks like you can't check boxes to Cancun - not really sure why :-/ Maybe ship it using FedEx/UPS/DHL/etc...

Did some more searching and found this, which might be another option:

Cargo on Jetblue (http://help.jetblue.com/SRVS/CGI-BIN/webisapi.dll/,/?St=73,E=0000000000015217118,K=3413,Sxi=11,Case=ob j(2233))

Cargo on JetBlue
Cargo may be carried in seats that have been purchased for the purpose of
carrying cargo when accompanied by a customer and by meeting the following
requirements:

Object has no sharp edges and is shaped so that it may be secured with a
seatbelt.
Object does not weigh more than what can easily be handled by one person
(up to 50 pounds).
Object is placed in a window seat, not in an exit seat, and does not obstruct
seat belt or no smoking signs.

Object is pre-boarded and deplaned after other customers have deplaned.

Welcome to FT!