Images
Image Testing in Emails
Neon Blue lets you test and personalize images inside email templates without requiring manual image selection per user. For each template, you choose one image section to personalize, upload a small set of approved images, and Neon Blue automatically selects and optimizes which image each user sees.
The key idea is simple: any image you upload for a template must be safe to use anywhere within the image section you choose to personalize.
What You Decide vs. What Neon Blue Handles
You decide:
Which image section in the email to make dynamic (header or body)
Which images are approved for that section
The target dimensions for that image section
Neon Blue handles:
Smart cropping and resizing
Per-user image selection based on performance
Choosing Which Images Are Dynamic
Dynamic images are ones where Neon Blue selects different images for different users. Each email template can be configured in one of three ways:
Dynamic header image with static body
Static header with dynamic body images
Both header and body images set to dynamic (advanced)
If both the header and body are dynamic, every image you upload must work in all possible placements. This requires stricter image curation and is typically only recommended for advanced use cases.
Core Rule: Image Pool Compatibility
For any dynamic image section, Neon Blue uses a single pool of approved images.
Important rule: Any image you upload may appear in any dynamic slot for that template. Only upload images you would be comfortable sending to any customer in that image section.
Because image selection is dynamic:
Every image must match the theme, message, and intent of the email
If an image is not appropriate for a specific placement, it should not be included
Neon Blue does not perform semantic or brand approval checks on images
How to Add Image Personalization
Select the image section to personalize Choose a single image section within the template to make dynamic. This can be a hero banner or a body image section. Only one image section per template is supported.
Upload approved images to the template’s media library Upload a pool of images specific to that template and image section. All uploaded images are considered eligible to appear in that section.
Recommended guidelines:
Multi-image body block (for example, 4 images), upload 4–12 images
Single hero or banner image, upload 2–3 images
Choose images that clearly support the email’s purpose and context.
Confirm crop dimensions Specify the target dimensions for the selected image section. Neon Blue automatically smart-crops all uploaded images to fit these dimensions, ensuring consistent rendering across users.
Once configured, Neon Blue AI dynamically selects and optimizes image delivery per user within the defined constraints.
Smart Cropping and Image Dimensions
All images uploaded to Neon Blue are automatically smart-cropped to match the dimensions required by the template.
This means you do not need to manually resize images perfectly. However:
Images that closely match the target aspect ratio will require less aggressive cropping
Better-matched images produce more consistent visual results
Dynamic Banner Images (Text on Image)
If your header image includes text rendered directly on the image, you must use a programmatic image template.
These templates ensure that text placement, contrast, and readability remain correct across all images. Refer to the Programmatic Image Templates section of the documentation for instructions on creating and validating these templates.
This requirement only applies to headers with text rendered on the image.
Dynamic Header Compatibility Requirements
When using a dynamic hero or header image, especially with text rendered on the image, all images in the image pool must match the header template’s dimensions and layout constraints.
Images that render correctly in body placements may still be incompatible with header placements due to differences in aspect ratio, focal point, or available space for text and logos.
Even with smart cropping enabled, images with mismatched dimensions or unsuitable composition may result in cropped or obscured logos, text rendering in unreadable or inappropriate areas, inconsistent visual output across users
Before enabling a dynamic header, confirm that every image in the pool:
Matches the header image dimensions or aspect ratio
Supports the fixed text and logo placement defined in the text-on-image template
Remains visually correct when used both in the header and in body placements
If an image does not meet these requirements, it should not be included in the image pool.
Email Body Images
Body image sections are generally more flexible than headers. If a template includes both dynamic headers and body images, header compatibility should be treated as the primary constraint when selecting images.
Once configured, Neon Blue automatically selects and optimizes image delivery per user based on performance and context.
Common Mistakes to Avoid
Uploading images that only work in one placement
Mixing text-safe and non-text-safe images in the same pool
Uploading too many images “just in case”
Including images that feel context-specific rather than broadly appropriate
If an image wouldn’t work everywhere in the selected image section, it shouldn’t be included.
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