使用Python发送带内嵌图片的邮件时Outlook客户端不显示图片怎么办

核心问题原因 #

• MIME结构不符合Outlook解析规范：你当前使用MIMEMultipart('alternative')作为根容器，该类型仅支持纯文本/HTML两种格式备选，无法兼容「内嵌资源+附件」的复合结构，Gmail对不规范结构容错性高可正常解析，Outlook严格遵循MIME标准因此无法匹配cid对应的图片
• 字段拼写错误：代码中Content-Decomposition应为Content-Disposition，octate-stream应为octet-stream，错误的头字段导致Outlook无法识别资源类型
• 同文件重复附加冲突：同一张figure.png同时作为内嵌资源和附件附加，未做标识区分时Outlook会优先识别为附件，导致HTML中的cid引用匹配失败
• 缺失依赖导入：原代码未导入MIMEBase和encoders模块，运行会抛出导入错误

修复后完整代码 #

from pretty_html_table import build_table
from email.mime.image import MIMEImage
from email.mime.multipart import MIMEMultipart
from email.mime.text import MIMEText
from email.mime.base import MIMEBase
from email import encoders
import smtplib

# 根容器使用mixed类型，支持同时存放正文、内嵌资源、附件
message = MIMEMultipart('mixed')
message['Subject'] = f"Data for {last_date.date()}"
message['From'] = sender
message['To'] = receiver

# 构建可选格式容器，存放纯文本/HTML备选内容
alt_part = MIMEMultipart('alternative')
message.attach(alt_part)

# 构建内嵌资源容器，存放HTML和对应的内嵌图片
related_part = MIMEMultipart('related')
alt_part.attach(related_part)

# 构建HTML表格
output_table = build_table(table_for_email, "blue_light")

html_content = MIMEText(
    f'''<html>
  <head></head>
  <body>
    <p>Hello!</p>
    <p>Please check out the new data.</p>
    {output_table}
    <!-- 可按需添加宽高属性，进一步提升Outlook兼容性 -->
    <img src="cid:plots" alt="数据图表">
  </body>
</html>
''', "html"
)
related_part.attach(html_content)

# 附加内嵌图片，标记为inline类型
image = MIMEImage(open('figure.png', 'rb').read())
image.add_header('Content-ID', '<plots>')
image.add_header('Content-Disposition', 'inline', filename='figure.png')
related_part.attach(image)

# 附加附件，修正拼写错误
attach_file_name = 'figure.png'
attach_file = open(attach_file_name, 'rb')
payload = MIMEBase('application', 'octet-stream')
payload.set_payload(attach_file.read())
encoders.encode_base64(payload)
payload.add_header('Content-Disposition', 'attachment', filename=attach_file_name)
message.attach(payload)

msg_body = message.as_string()

server = smtplib.SMTP_SSL(mail_server)
server.login(sender, password)
server.sendmail(from_addr=sender, 
                to_addrs=receiver, 
                msg=msg_body)

server.quit()

内容的提问来源于stack exchange，提问作者Lasha Dolenjashvili