It seems like you have some concerns about the payment practices of your small business and how it affects independent contractors, specifically the photographer. Let's break down your questions and provide some insights:

1. Should independent contractors be paid immediately when the work is done?
There is no universal rule for payment terms between businesses and independent contractors. However, it is generally considered good practice to pay contractors promptly, especially if they are small businesses or sole proprietors. Timely payment helps maintain good relationships, encourages future collaborations, and supports the financial stability of the contractor. 

2. Should all small businesses be paid as soon as possible?
Again, there is no hard and fast rule, but paying small businesses promptly can have positive effects. Small businesses often have limited cash flow and rely on timely payments to cover their expenses and grow their operations. By paying small businesses promptly, you contribute to their success and help build a strong entrepreneurial ecosystem.

3. How quickly do businesses pay/expect to be paid in a B2B context?
Payment terms in B2B relationships can vary depending on various factors such as industry norms, business size, and negotiation between parties. Some businesses may have net-30 (payment due within 30 days) or net-60 payment terms, while others may require immediate payment or offer discounts for early payment. It's important to establish clear payment terms and expectations upfront to avoid misunderstandings or strained relationships.

In your specific situation, it appears that your boss has a different perspective on payment practices, which can create tension. It might be helpful to have an open conversation with your boss to understand their reasoning behind the payment delays and express your concerns about the impact it has on the relationships with contractors. Additionally, you can research industry standards or consult with other professionals in your field to gather more insights and references to support your viewpoint.

Remember, every business operates differently, and what works for one may not work for another. It's crucial to find a balance that aligns with your company's financial capabilities while also considering the needs and expectations of your contractors.