How to resolve embedded graphics and PNG preview issues in Mail on macOS Sequoia?

DarkValley wrote:

A previous question to the forum indicated that email containing embedded pictures/graphics are not showing in Mail (version 16.0 (3826.400.131.1.6))and there seems to be no way to ask them to be downloaded either automatically or on demand. I just updated to Sequoia 15.3.2 and both my machines show the same problem A web search does not lead to any useful suggestions.

The other problem that the update introduced is that PNG files no longer have a preview showing - just the generic icon. The file opens correctly with the picture. Again, a web search gives no useful ideas or solutions.

[Re-Titled by Moderator]

I thought I noticed the same thing in attaching an png to mail—

this seemed to work from the Terminal.app copy and paste:

defaults write com.apple.mail DisableInlineAttachmentViewing -bool false

for incoming mail not showing—

Open Mail.app

from the menu bar select Mail>Settings>Privacy and disable:

Block all remote content (and compare your results)

if no resolve these too—

Protect Mail Activity

Hide IP address

quit and relaunch Mail if necessary hold the Shift key down

DarkValley wrote:

The terminal command sorted out the problems with Mail not showing embedded graphics. Note that this needs to be done using sudo. Thanks.

This change does not affect the preview of PNG files. That is still a problem.

Good computing—

Thanks for your note DarkValley— I would have expected if in an admin account the command-line tool would have worked; but I will make a note of it.

I will keep my eye open for a resolve with your Preview.app and .png— it is a curiosity...

I believe the default screenshot is the .png — same issue with Preview(?) this can be changed

From the Terminal.app

You can see the default setting, copy and paste 

defaults read com.apple.screencapture type

make change to some other like jpg then come back to your preferred setting here the example is .png

copy and paste:

defaults write com.apple.screencapture type png && killall SystemUIServer

is this both QuickLook of .png and Preview or just Preview?

You can try >Force Quitting the Preview.app and try again

A SafeBoot Start up your Mac in safe mode - Apple Support will sort many anomalies

Login and test. Reboot  as normal and test. 

Luis Sequeira1 wrote:

I could be wrong but I interpreted the issue as the Finder icons of png files not showing a thumbnail version of the image, not a problem with Preview or Quicklook.

thanks— i did not go back to read the OP. you are right

in this case I would suggest to DarkValley try changing the size of the icons— all the way one way or the other and see if it elicits a change...

I could be wrong but I interpreted the issue as the Finder icons of png files not showing a thumbnail version of the image, not a problem with Preview or Quicklook.