How to fix broken image links in incoming e-mails?

[comphernation]

I sometimes receive e-mails with a a blue '?' box in place of an expected graphic image. An affected message's raw source code shows it's broken up by '=' characters. Here's an example from a MailChimp message (it happens with other senders, too):

563 align=3D
left
=

 class=3D
mcnImage
 style=3D
padding-bottom: 0px;vertical-align: bottom;di=

splay: inline !important;max-width: 671px;border: 0;outline: none;text-dec=

oration: none;-ms-interpolation-mode: bicubic;
 alt=3D
 src=3D
https://ga=

llery.mailchimp.com/9fde367fdd6ae4d9d725f787d/images/5ffabb62-a1f2-47e5-ba=

ff-4a70ffd85149.jpg
>

What causes this?

Anything I can fix on my end? Otherwise, what might I ask a sender to change?

Thanks!

[modelamac]

Does it happen with Mail.app or Thunderbird? You have to isolate the source. It happens at the Server or in your Mac. If another mail app (client) does the same thing, it is a server problem and you can do nothing about it except to complain to them. Otherwise it is on your Mac and you need to rebuild your Inbox or Repair Disk.

See Mac Help on your Mac.

If this suddenly happened, what did you do on your Mac recently? What changes did you make? What software did you add about the same time this began?

You can test for this "change" by setting up a Test user account on your Mac and seeing if it happens there. If not, then the problem is in your User account.

Report back with your findings.

[comphernation]

I thought I had mentioned using Mail.app but apparently edited that out without noticing. Turns out it wouldn't have mattered, as I discovered the cause a little while after posting.

Checking into Little Snitch, I saw that back in Feb. 2012 I made a rule to block imgssl.constantcontact.com on TCP port 443 (https). But I goofed and set it to block 443 on _any_ domain, not just constantcontact. So when mailchimp.com came along it got blocked, too. I've fixed my error, and all's well.

Thanks for taking time to try to help me. I appreciate it!

[comphernation]

Oh, and for anyone playing along at home, while it looks like the '=' line endings break up the links, apparently Mail.app handles them fine anyway.