Why doesn't zimbra display tiff images in email sent from OS X via Apple mail client?

Question

Zimbra

When sending letters with pictures (screenshots), all pictures come in tiff, and as a result are not displayed in zimbra web mail.
I tried to look at the source code of the page and found 2 options for how pictures come:
1. link to the attachment, if you follow this link, then tiff is downloaded and you can then open it

<img id="AE4B706E-6EC1-4694-89DC-0191151E225D" height="324" width="324" pnsrc="cid:[email protected]" class="" src="https://mail.domain.ltd/service/home/~/?auth=co&amp;id=40062&amp;part=2.2">

2. There is no link, instead strange html attributes are used for me:

<img id="A1BF7486-F353-428E-B1DA-4C67484B4BCE" height="960" width="1003" pnsrc="cid:[email protected]" class="">

Is there a way to fix this?