lib/Mailer/SendGrid.php
protected function processAttachments(array $attachments)
    {
        $attachments = AttachmentUtils::processAttachments($attachments);
        $processedAttachments = [];

        foreach ($attachments as $name => $attachment) {
            $item = [
                'content'  => base64_encode(file_get_contents($attachment->getPath())),
                'type'     => $attachment->getType(),
                'filename' => $attachment->getName(),
            ];

            $id = $attachment->getId();
            if (!empty($id)) {
                $item['disposition'] = 'inline';
                $item['content_id'] = $id;
            }

            $processedAttachments[] = $item;
        }

        return $processedAttachments;
    }
protected function processAttachments(array $attachments)
    {
        $attachments = AttachmentUtils::processAttachments($attachments);
        $processedAttachments = [];

        foreach ($attachments as $name => $attachment) {
            $item = [
                'content'  => base64_encode(file_get_contents($attachment->getPath())),
                'type'     => $attachment->getType(),
                'filename' => $attachment->getName(),
            ];

            $id = $attachment->getId();
            if (!empty($id)) {
                $item['disposition'] = 'inline';
                $item['content_id'] = $id;
            }

            $processedAttachments[] = $item;
        }

        return $processedAttachments;
    }
@param Attachment[] $attachments

@return array First element: All attachments – array(name => path). Second element: Inline attachments – array(id => name)