No consideration, no contract. Unless and until they provide valuable consideration, they can't even claim an enforceable verbal contract.

You are not obliged to provide them with anything at this point, and should be legally entitled to prevent them from using any work you have provided (JPEGs, etc.) to date since copyright in the images still resides with you (even under laws as stupidly client-biased as the ones we have here in Canada).

If it were the case that they provided consideration (payment or the equivalent), or that there was a contract that involved consideration on their part not yet given, but provided for (subject to delivery or what have you), then your rights would depend on jurisdiction as well as the warrants of the contract. (In Canada, for instance, the copyright for photography rests with the commissioner of the work barring a legal agreement to the contrary, and would be entitled to everything.)

As other people have said, though, I hope this ends your "on spec" career. It's perfectly fine to give your work away (in the charitable sense), but when you work on spec you'll always come out the loser—there will never be anything more than auditions.