PHPMailer addStringEmbeddedImage and adding the same image more than once - php

Question

So in PHPmailer you can add a 64base coded image to the mail's body if you use addStringEmbeddedImage and in the data part you base64_decode the image. Ex:
$mail->addStringEmbeddedImage(base64_decode($str), "img_".$i, "img_".$i,"base64",$type);
I get the images from my text editor in base64 form and then replace the image with the respective container
<img src=\"cid:img_".$i."\" ".$height. " " .$width. ">"
And it works fine but for some reason, as soon as I add an image more than one time, it doesn't matter if its the very next image or first and last one, the mail will just save(?) the first image. Is not that it doesn't show it because in the original mail you can see that there's only 1 container specified in it.
--boundary
Content-Type: image/png; name="img_1"
Content-Transfer-Encoding: base64
Content-ID: <img_1>
Content-Disposition: inline; filename="img_1"
As you can see, each image has a different id (which is the order they are in the email) and the only way it can tell it is the same image is by the decoded base64 image so i really dont know why this only happens when its the same image. I could add img1----img2----img1----img3 and it will show img1 ---- img2---- |emptycontainer|---- img3
Edit: So for reference, this is the while I use to extract all the images
//$body of the mail, all the images i want to replace have that alt"" at the start
while(strstr($body, "<img alt")){
$i++;
$start= strpos($body, "<img alt");
$end= strpos($body,">",$start);
$str = substr($body,$start,$end-$start);
$height = "";
$width = "";
if (strstr($str, "height:")){
$ini = strpos($str, "height:")+7;
$fin = strpos($str,";",$ini);
$height = "height= \"".substr($str,$ini,$fin-$ini-2)."\"";
}
if (strstr($str, "width:")){
$ini = strpos($str, "width:")+6;
$fin = strpos($str,"\"",$ini);
$width = "width= \"".substr($str,$ini,$fin-$ini-2)."\"";
}
//here i replace the whole image with a container
$body= substr_replace($body, "<img src=\"cid:img_".$i."\" ".$height. " " .$width. ">", $start,$end-$start+1);
//get the type after data:
$start= strpos($str, "data:");
$end= strpos($str,";",$start);
$type= substr($str, $start+5, $end-$start-5);
//and this is where i get the base64 string
$start= strpos($str, "base64,");
$end= strpos($str,"\"",$start);
$str = substr($str, $start+7, $end-$start-7);
$mail->addStringEmbeddedImage(base64_decode($str), "img_".$i, "img_".$i,"base64",$type);
}
I appreciate any help and thanks for reading

Answer 1

I can see why you would use the same image more than one in a message, but why would you attach the same image more than once to achieve that? Much of the point of cid values is that they allow you to reference the same image from multiple places, so if say you have a logo image that appears in both header and footer, you can attach it once and reference it from both places, reducing message size. I suspect your issue is that you're trying to work around this and failing by attaching the same image data with two cid values, but PHPMailer is noticing the data is the same and not doing the second attachment, leaving your second cid pointing at nothing. You can fix it by using the same cid value for both image tags.
This should have the problem you mention:
$img = base64_decode($str);
$mail->addStringEmbeddedImage($img, "img_1", "img_1", "base64", $type);
$mail->addStringEmbeddedImage($img, "img_2", "img_2", "base64", $type);
<img src="cid:img_1">
<img src="cid:img_2">
This should work:
$img = base64_decode($str);
$mail->addStringEmbeddedImage($img, "img_1", "img_1", "base64", $type);
<img src="cid:img_1">
<img src="cid:img_1">
The code calculates an SHA256 hash of the content and uses that to check whether they are the same.