An image map groups a set of pre-defined target OS specifications for a specific cloud account/region using natural language naming.
Cloud vendor accounts such as Microsoft Azure and Amazon Web Services use images to group a set of target deployment conditions together, including OS and related configuration settings. vCenter and NSX-based environments, including VMware Cloud on AWS, use a similar grouping mechanism to define a set of OS deployment conditions.
Image mapping lets you create a named mapping that contains pre-defined OS configurations across your account regions. For example, an image map named Ubuntu_projabx might contain a similar Ubuntu OS configuration for some or all of the available account/regions in your project. See WordPress Use Case: Add Image Mappings.
You can display your image mappings by either image name or by account/region.
When you build and eventually deploy and iterate a blueprint, you pick an available image that best fits your needs.
You should organize the image mappings for your project by similar OS settings and by functional deployment intent.