Outlook - Images not showing in signature of original mail when replying - email

Question

I have made an email signature in Outlook (2016) by pasting HTML in the window where one can type a new signature (File>Options>Email>Signatures>New).
It looks good when sending a mail, it shows all images. The receiver of the mail (on any other mail client but Outlook, e.g. on Apple Mail or Gmail) can see the images too, but when this receiver using Apple Mail or so is going to reply to this mail, the images in the signature of the originally sent email have disappeared and have been replaced by
<image001.png> (referring to images saved locally within C:\Users\[name]\AppData\Roaming\Microsoft\Signatures, in the respective [signature name]_files folder, while the src of the original <img/>s in the signature are URLs to actual accessible files on the web). These images can be displayed anyway by clicking a button to 'include attachments of the original mail', which is, let's say, weird. It apparently turns the images in Outlook-signatures into attachments, which are being blocked or so, as it seems.
Has anyone had a comparable problem, and/or is kind to share a solution for this issue?
Thank you in advance.

Answer 1

Try adding ? and then a random number at the end of your image URL. Also, make sure you are using a CDN to deliver the image. I use cloudinary.com...
Here is an example of what I did...
<table cellPadding="0" cellSpacing="0">
<tbody>
<tr>
<td style="vertical-align:top"></td>
<td>
<div><font size="4">Name</font></div>
<div>Title</div>
<div><span style="margin-right:8px">phone</span></div>
<div><span style="margin-right:8px"><a style="color:blue" href="mailto:email">email</a></span></div>
<div><span style="margin-right:8px">address</span></div>
<div style="padding: 0 0em 2em 0;">
<img src="http://CDN/Facebook.jpg?7" alt="Facebook" />
<img src="http://CDN/Twitter.jpg?5" alt="Twitter" />
<img src="http://CDN/Instagram.jpg?3" alt="Instagram" />
<img src="http://CDN/Linkedin.jpg?2" alt="LinkedIn" />
</div>
</td>
</tr>
</tbody>
I open this HTML in my web browser, copy and paste it into the signature section of Outlook. One caveat.. I am using the Outlook Web Browser for my email, not the Application.
I have been testing:
Outlook -> Gmail -> Outlook, and my signature stays intact.
So far this has been working for 2 days. I am going to keep testing but give it a shot and let me know if you see the same good results.