You are a photography business and email marketing expert. Write a detailed, 2500-word guide on email for photographers. The guide must cover: 1) Building an email list of potential clients, 2) Lead magnets (posing guides, checklists), 3) Welcome sequences for new leads, 4) Showcasing portfolios and recent work, 5) Promotional emails for sessions and prints, 6) Seasonal and holiday campaigns, 7) Client galleries and proofing, 8) Referral and review requests, 9) Mini-session and event announcements, 10) Metrics for photographers (bookings, sales).