diff --git a/SwiftMailer/MessageFormat/MessagePayloadV3.php b/SwiftMailer/MessageFormat/MessagePayloadV3.php
index 6a90b0f..b65af3e 100644
--- a/SwiftMailer/MessageFormat/MessagePayloadV3.php
+++ b/SwiftMailer/MessageFormat/MessagePayloadV3.php
@@ -5,6 +5,7 @@
 use \Swift_Mime_SimpleMessage;
 use \Swift_Attachment;
 use \Swift_MimePart;
+use \Swift_Image;
 
 class MessagePayloadV3 extends BaseMessagePayload {
 
@@ -41,23 +42,20 @@ public function getMailjetMessage(Swift_Mime_SimpleMessage $message) {
 
         // Handle attachments
         foreach ($message->getChildren() as $child) {
-            if ($child instanceof Swift_Attachment) {
-                //Handle regular attachments
-                if ($child->getDisposition() === "attachment") {
-                    $attachments[] = array(
-                        'Content-type' => $child->getContentType(),
-                        'Filename' => $child->getFilename(),
-                        'content' => base64_encode($child->getBody())
-                    );
-                }
-                //Handle inline attachments
-                elseif ($child->getDisposition() === "inline") {
-                    $inline_attachments[] = array(
-                        'Content-type' => $child->getContentType(),
-                        'Filename' => $child->getFilename(),
-                        'content' => base64_encode($child->getBody())
-                    );
-                }
+            if (($child instanceof Swift_Attachment || $child instanceof Swift_Image)
+                && $child->getDisposition() === "inline"
+            ) {
+                $inline_attachments[] = array(
+                    'Content-type' => $child->getContentType(),
+                    'Filename' => $child->getFilename(),
+                    'content' => base64_encode($child->getBody())
+                );
+            } elseif ($child instanceof Swift_Attachment && $child->getDisposition() === "attachment") {
+                $attachments[] = array(
+                    'Content-type' => $child->getContentType(),
+                    'Filename' => $child->getFilename(),
+                    'content' => base64_encode($child->getBody())
+                );
             } elseif ($child instanceof Swift_MimePart && $this->supportsContentType($child->getContentType())) {
                 if ($child->getContentType() == "text/html") {
                     $bodyHtml = $child->getBody();
diff --git a/SwiftMailer/MessageFormat/MessagePayloadV31.php b/SwiftMailer/MessageFormat/MessagePayloadV31.php
index e25385d..5d08f52 100644
--- a/SwiftMailer/MessageFormat/MessagePayloadV31.php
+++ b/SwiftMailer/MessageFormat/MessagePayloadV31.php
@@ -4,6 +4,7 @@
 
 use \Swift_Mime_SimpleMessage;
 use \Swift_Attachment;
+use \Swift_Image;
 use \Swift_MimePart;
 
 class MessagePayloadV31 extends BaseMessagePayload {
@@ -72,7 +73,16 @@ public function getMailjetMessage(Swift_Mime_SimpleMessage $message) {
 
         // Handle attachments
         foreach ($message->getChildren() as $child) {
-            if ($child instanceof Swift_Attachment) {
+            if (($child instanceof Swift_Attachment || $child instanceof Swift_Image)
+                && $child->getDisposition() === "inline"
+            ) {
+                $inline_attachments[] = array(
+                    'ContentType' => $child->getContentType(),
+                    'Filename' => $child->getFilename(),
+                    'ContentID' => $child->getId(),
+                    'Base64Content' => base64_encode($child->getBody())
+                );
+            } elseif ($child instanceof Swift_Attachment) {
                 //Handle regular attachments
                 if ($child->getDisposition() === "attachment") {
                     $attachments[] = array(
@@ -82,14 +92,6 @@ public function getMailjetMessage(Swift_Mime_SimpleMessage $message) {
                     );
                 }
                 //Handle inline attachments
-                elseif ($child->getDisposition() === "inline") {
-                    $inline_attachments[] = array(
-                        'ContentType' => $child->getContentType(),
-                        'Filename' => $child->getFilename(),
-                        'ContentID' => $child->getId(),
-                        'Base64Content' => base64_encode($child->getBody())
-                    );
-                }
             } elseif ($child instanceof Swift_MimePart && $this->supportsContentType($child->getContentType())) {
                 if ($child->getContentType() == "text/html") {
                     $bodyHtml = $child->getBody();
diff --git a/Tests/SwiftMailer/MailjetTransportv31Test.php b/Tests/SwiftMailer/MailjetTransportv31Test.php
index 65293cf..6e6ccb9 100644
--- a/Tests/SwiftMailer/MailjetTransportv31Test.php
+++ b/Tests/SwiftMailer/MailjetTransportv31Test.php
@@ -209,6 +209,24 @@ public function testMessage() {
         $this->assertMessageSendable($message);
     }
 
+    public function testInlineImage() {
+        $transport = $this->createTransport();
+        $message = new \Swift_Message('Test Subject', '<p>Foo bar</p>', 'text/html');
+        $inline_image = new \Swift_Image($this->createPngContent(), 'filename.png', 'image/png');
+        $message->attach($inline_image);
+        $message
+                ->addTo('to@example.com', 'To Name')
+                ->addFrom('from@example.com', 'From Name')
+        ;
+        $mailjetMessage = $transport->messageFormat->getMailjetMessage($message)['Messages'][0];
+
+        $transport->send($message);
+
+        $this->assertMailjetMessageContainsInlineAttachment('image/png', 'filename.png', $this->createPngContent(), $mailjetMessage);
+
+        $this->assertMessageSendable($message);
+    }
+
     public function testBulkSendMessages() {
         $transport = $this->createTransport();
 
diff --git a/composer.json b/composer.json
index 050bf91..7541f88 100644
--- a/composer.json
+++ b/composer.json
@@ -11,7 +11,7 @@
     },
     "require-dev": {
         "phpunit/phpunit": "^5.7",
-        "symfony/config": ">=2.0|~3.0"
+        "symfony/config": "^3.4"
     },
     "license": "MIT",
     "authors": [