Most images embedded in HTML messages appear just fine. But occasionally a screenshot appears to be totally overexposed / washed out when the underlying image file looks perfectly fine.
STEPS TO REPRODUCE
1. Take a screenshot of something in your browser (I used Flameshot).
2. Embed the picture in an email message.
3. Send it to yourself, then look at it.
Sometimes the image looks all washed out, even when the original image looks good.
I expect all the embedded images in an HTML-encoded message to be displayed sharply and clearly.
Linux/KDE Plasma: *
(available in About System)
KDE Plasma Version: 5.20.5
KDE Frameworks Version: 5.80.0
Qt Version: 5.15.2
See attached screenshots, which I'll upload in a minute or two. I'll also upload the raw email message file.
Created attachment 137634 [details]
Screenshot of a washed-out image
This is a screenshot of an image as it appears in the normal HTML display.
Created attachment 137635 [details]
Screenshot of the same image when displayed as an attachment not embedded in an email message.
This is what the image looks like when I view the attachment in the KMail preview pane as a separate item, and not as part of a message.
Created attachment 137636 [details]
The raw email message (.mbox format, but called .txt).
This is the raw email message I used to make the two preceding screenshots.
Let me know if you want more examples. I'll do some goofing around with other image creation programs (Spectacle, Firefox "screenshot" tool, etc.) if you think that might be helpful. This doesn't happen very often, and only seems to occur when I create a screenshot myself. (In this instance, I uploaded an image to the groups.io web site, and sent the email message from the web site.) Thanks!
More information. This *only* happens with one sender. In most of the messages that I receive the images are fine. But if the message originates from http://groups.io, this error pops up. I'll ask about it at the groups.io web site.