I set-up a Google Gmail account and forward my picture messages that way using their email filters. When I mail the account from my Cricket phone, it automatically gets forwarded to my Cincinnati Bell phone and vice versa.
It used to work directly between the two services, but that stopped some time ago.
If you know how to set-up your email client and its rules/filters, you can do the same thing.
An ugly workaround, but it works!