do passport photos for i130 supporting evidence have to be dated?

[shmuelrosen]

The i130 requires a passport photo of my spouse and i taken within 30 days of filing, but the photos arent dated - will they be accepted?
if not can i just write the date on the back?

[kgingras]

When I sent mine in I included a copy of the receipt of when and where the photos were taken.