diff --git a/htdocs/lib/CMailFile.class.php b/htdocs/lib/CMailFile.class.php
index 405fa3f130ae6c0a2c046165dbd1b04b240505b9..be9aea6cf4fc950d081f148f5271af92f6d8bcf0 100644
--- a/htdocs/lib/CMailFile.class.php
+++ b/htdocs/lib/CMailFile.class.php
@@ -113,13 +113,13 @@ class CMailFile
 		if (preg_match('/^mac/i',PHP_OS)) $this->eol="\r";
 
 		// On defini mixed_boundary
-		$this->mixed_boundary = md5(uniqid("dolibarr"));
+		$this->mixed_boundary = md5(uniqid("dolibarr1"));
 
 		// On defini related_boundary
-		$this->related_boundary = md5(uniqid("dolibarr"));
+		$this->related_boundary = md5(uniqid("dolibarr2"));
 
 		// On defini alternative_boundary
-		$this->alternative_boundary = md5(uniqid("dolibarr"));
+		$this->alternative_boundary = md5(uniqid("dolibarr3"));
 
 		// If ending method not defined
 		if (empty($conf->global->MAIN_MAIL_SENDMODE)) $conf->global->MAIN_MAIL_SENDMODE='mail';
@@ -207,13 +207,13 @@ class CMailFile
 
 			// Define body in text_body
 			$text_body = $this->write_body($msg);
-			$text_body.= "--" . $this->alternative_boundary . "--" . $this->eol;
+			if (! empty($conf->global->MAIN_MAIL_EMAIL_INLINE_IMAGES)) $text_body.= "--" . $this->alternative_boundary . "--" . $this->eol;
 
 			// Encode images
 			if ($this->atleastoneimage)
 			{
 				$images_encoded = $this->write_images($this->images_encoded);
-				$images_encoded.= "--" . $this->related_boundary . "--" . $this->eol;
+				if (! empty($conf->global->MAIN_MAIL_EMAIL_INLINE_IMAGES)) $images_encoded.= "--" . $this->related_boundary . "--" . $this->eol;
 			}
 
 			// Add attachments to text_encoded
@@ -603,21 +603,24 @@ class CMailFile
 		$out.= "Content-Type: multipart/mixed; boundary=\"".$this->mixed_boundary."\"".$this->eol;
 		$out.= "Content-Transfer-Encoding: 8bit".$this->eol;
 		
-		if ($this->atleastoneimage)
+		if (! empty($conf->global->MAIN_MAIL_EMAIL_INLINE_IMAGES))
 		{
-			$out.= "--" . $this->mixed_boundary . $this->eol;
-			$out.= "Content-Type: multipart/related; boundary=\"".$this->related_boundary."\"".$this->eol;
+			if ($this->atleastoneimage)
+			{
+				$out.= "--" . $this->mixed_boundary . $this->eol;
+				$out.= "Content-Type: multipart/related; boundary=\"".$this->related_boundary."\"".$this->eol;
+				$out.= $this->eol;
+				$out.= "--" . $this->related_boundary . $this->eol;
+			}
+			else
+			{
+				$out.= "--" . $this->mixed_boundary . $this->eol;
+			}
+
+			$out.= "Content-Type: multipart/alternative; boundary=\"".$this->alternative_boundary."\"".$this->eol;
 			$out.= $this->eol;
-			$out.= "--" . $this->related_boundary . $this->eol;
-		}
-		else
-		{
-			$out.= "--" . $this->mixed_boundary . $this->eol;
 		}
 		
-		$out.= "Content-Type: multipart/alternative; boundary=\"".$this->alternative_boundary."\"".$this->eol;
-		$out.= $this->eol;
-
 		//$out.=$this->eol;	// Comment this to try to solve pb of hidden attached files. New line must be after the X-attachments
 		dol_syslog("CMailFile::write_smtpheaders smtp_header=\n".$out);
 		return $out;
@@ -666,12 +669,14 @@ class CMailFile
 
 		if ($this->msgishtml)
 		{
-			$out.= "--" . $this->alternative_boundary . $this->eol;
+			if (! empty($conf->global->MAIN_MAIL_EMAIL_INLINE_IMAGES)) $out.= "--" . $this->alternative_boundary . $this->eol;
+			else $out.= "--" . $this->mixed_boundary . $this->eol;
 			$out.= "Content-Type: text/html; charset=".$conf->file->character_set_client.$this->eol;
 		}
 		else
 		{
-			$out.= "--" . $this->alternative_boundary . $this->eol;
+			if (! empty($conf->global->MAIN_MAIL_EMAIL_INLINE_IMAGES)) $out.= "--" . $this->alternative_boundary . $this->eol;
+			else $out.= "--" . $this->mixed_boundary . $this->eol;
 			$out.= "Content-Type: text/plain; charset=".$conf->file->character_set_client.$this->eol;
 		}
 		$out.= $this->eol;
@@ -693,7 +698,7 @@ class CMailFile
         $strContent = rtrim(wordwrap($strContent));
 
 		$out.= $strContent.$this->eol;
-		$out.= $this->eol;
+		if (! empty($conf->global->MAIN_MAIL_EMAIL_INLINE_IMAGES)) $out.= $this->eol;
 
 		return $out;
 	}
@@ -759,7 +764,8 @@ class CMailFile
 			{
 				dol_syslog("CMailFile::write_images: i=$i");
 
-				$out.= "--" . $this->related_boundary . $this->eol;
+				if (! empty($conf->global->MAIN_MAIL_EMAIL_INLINE_IMAGES)) $out.= "--" . $this->related_boundary . $this->eol;
+				else $out.= "--" . $this->mixed_boundary . $this->eol;
 				$out.= "Content-Type: " . $img["content_type"] . "; name=\"".$img["name"]."\"".$this->eol;
 				$out.= "Content-Transfer-Encoding: base64".$this->eol;
 				$out.= "Content-Disposition: inline; filename=\"".$img["name"]."\"".$this->eol;