Add support for inline embedded images in email_send_message function #17789
Description
related to #17788
Current Behavior
The email_send_message function in prefect-email currently only supports sending images as attachments using the attachments parameter, which adds files with Content-Disposition: attachment.
Proposed Enhancement
Extend the function to support embedding images inline within HTML email content using the Content-ID mechanism and MIME multipart/related structure.
- Add a new parameter to
email_send_message:inline_images: Optional[dict[str, str]] = None
where keys are content IDs and values are file paths
For each inline image:
Read the image file and create a MIMEImage part
Set the Content-ID header with the specified ID
Add the part to the message with proper MIME structure
The implementation would look something like:
from email.mime.image import MIMEImage
# Add after handling attachments
for cid, filepath in (inline_images or {}).items():
with open(filepath, "rb") as img_file:
img = MIMEImage(img_file.read())
img.add_header('Content-ID', f'<{cid}>')
img.add_header('Content-Disposition', 'inline')
message.attach(img)Example Use
email_send_message(
email_server_credentials=credentials,
subject="Report with Chart",
msg="""
<html>
<body>
<p>Here's the monthly chart:</p>
<img src="cid:chart1">
</body>
</html>
""",
email_to="recipient@example.com",
inline_images={"chart1": "/path/to/chart.png"}
)Additional context
This should be possible using only the stdlib email library we're already using