i am a subcontrator for a installation company. Recently there have been many changes in the way we "complete" an installation.

my question is this may a contractor hold a paycheck from a subcontractor for something trivial like not sending in pictures of an install even though the work was performed and the contractor has been paid for it?

and pictures were not required untill very recently and i have been working for them for over 3 years

The employer is entitled to impose additional requirements on the employee at any time, even if you had not had to send the picture before.

Whether your check can be held, however, depends on whether you are an employee or an independent contractor. If you are an employee, no they cannot, and you can file a claim for unpaid wages with the state Dept. of Labor. If you are an IC, the terms and conditions of payment should be spelled out in your contract.

it is not part of the contract it is a very recent condition...there have been many changes recently and everytime a new condition comes through we are threatened with check holding until we comply
and i am an ic

Then you will have to sue for payment, just like any other vendor. Or, just comply with the new requirements.

i am complying with the requirements thats not the question...

the question is can he legally hold payment for jobs allready completed in order to force the compliance

That's going to be for a court to decide. Since you are not an employee, wage and hour laws do not apply to you.