Act as an email marketing strategist and email designer. Create a comprehensive guide for using images and visuals effectively in email campaigns for a [business type] in the [niche/industry] targeting [target audience] with the goal of [content goal/business goal]. Align recommendations with the following design inputs: [brand colors], [brand fonts] and [visual style]. Develop practical guidelines designed to improve visual communication, engagement and conversion while maintaining performance and accessibility. Cover areas such as image selection, visual hierarchy, image-to-text balance, file formats, load times, responsiveness, accessibility, dark mode behavior, alt text, CTA visibility and compatibility across email clients. Include recommendations for balancing aesthetics with readability, supporting the message through visuals and avoiding common email rendering issues. Organize the output into clear design categories with best practices, examples and implementation recommendations. Keep the guide practical, visually cohesive and easy to apply.