RCW 82.08.02087: 
"A photographer is not required to collect sales tax when each of the following is true: 
1. The customer is a business, and
2. The customer will use the photo solely for business purposes, and
3. The photo is delivered electronically, and
4. The customer provides the seller with a completed certificate (below)"

Sales Tax Exemption Form

Please print this out and mail to:
Caffery Photo
724 So 30th Ave
Yakima, WA 98902