Implements a mailer preview interceptor that converts image tag src attributes that use inline cid: style urls to data: style urls so that they are visible when previewing a HTML email in a web browser.

This interceptor is not enabled by default, to use it just register it like any other mailer preview interceptor:

ActionMailer::Base.register_preview_interceptor(ActionMailer::InlinePreviewInterceptor)
Included Modules
Constants
PATTERN = /src=(?:"cid:[^"]+"|'cid:[^']+')/i