!1279 修复MailUtil发送html格式邮件无法正常展示图片问题

* bugfix mail:图片附件设置内联,能够正常引用附件图片
* bugfix mail:图片附件设置内联,能够正常引用附件图片

hutool-extra/src/test/java/cn/hutool/extra/mail/JakartaMailTest.java

@@ -38,6 +38,15 @@ public class JakartaMailTest {
 		JakartaMailUtil.sendHtml("hutool@foxmail.com", "测试", "<h1>邮件来自Hutool测试</h1><img src=\"cid:testImage\" />", map);
 	}
 
+	@Test
+	@Disabled
+	public void sendHtmlWithImageTest() {
+		Map<String, InputStream> map = new HashMap<>();
+		InputStream in = getClass().getClassLoader().getResourceAsStream("image/Dromara.png");
+		map.put("<image-1>", in);
+		JakartaMailUtil.sendHtml("hutool@foxmail.com;li7hai26@outlook.com", "测试", "<h1>邮件来自Hutool测试</h1><img src=\"cid:image-1\" />", map);
+	}
+
 	@Test
 	@Disabled
 	public void sendHtmlTest() {

hutool-extra/src/test/java/cn/hutool/extra/mail/MailTest.java

@@ -38,6 +38,15 @@ public class MailTest {
 		MailUtil.sendHtml("hutool@foxmail.com", "测试", "<h1>邮件来自Hutool测试</h1><img src=\"cid:testImage\" />", map);
 	}
 
+	@Test
+	@Disabled
+	public void sendHtmlWithImageTest() {
+		Map<String, InputStream> map = new HashMap<>();
+		InputStream in = getClass().getClassLoader().getResourceAsStream("image/Dromara.png");
+		map.put("<image-1>", in);
+		MailUtil.sendHtml("hutool@foxmail.com;li7hai26@outlook.com", "测试", "<h1>邮件来自Hutool测试</h1><img src=\"cid:image-1\" />", map);
+	}
+
 	@Test
 	@Disabled
 	public void sendHtmlTest() {