Umbraco is taking:
<img alt="Your Title - for example Mr., Mrs., Ms."
src="../media/21283/q16x16.gif" width="16" height="15"/>
And turning it into
<img alt="" src="/media/21283/q16x16.gif" width="16" height="15" rel="16,15"/>
If I alter the alt tag after this processing then the alt tag is saved.
My guess is this has something to do with the 'validElements' setting in TinyMCE (the wysiwyg editor)
in version 4 this is edited in the /config/tinyMCEConig.config file. Look for validElements. It could be the same in 3.03?
Each allowed HTML tag along with it's allowed attributes is listed in this section in the config file. Ensure you have a something like this in there:
img[id|dir........border|alt=|title.......]