I am having this same problem. This was not a problem in an earlier version of my app running on the same server as the latest version. Anytime I save items with a rich text field, the quote marks are escaped.
I enter the following code:
<p><img src="/images/Demo/iZ3.jpg" alt="" width="1368" height="768" /></p>
Press SAVE and the get the following code back:
<p><img src=\"/images/Demo/iZ3.jpg\" alt=\"\" width=\"1368\" height=\"768\" /></p>
I tried changing editors and even used the No Editor option. I tried it from both the front and back end and got the same results. I tried it with different user accounts (registered & special).
Running Joomla 2.5.27
Editors: No Editor and JCE
When I tested this in the sandbox, it does not happen.
Any ideas?
ADDITIONAL
I just tried to save an item multiple times in a row and fond that the problem becomes worse every time I save the item.
<p><img src=\\\\\"/images/Demo/iZ3.jpg\\\\\" alt=\\\\\" \\\\\" width=\\\\\" 1368\\\\\" height=\\\\\" 768\\\\\" /></p>