This one took a little futzing around and digging through the TinyMCE forum to figure out, but it’s been nagging at me for a while. By default (or at least in the default configuration provided under the LG TinyMCE extension for ExpressionEngine), TinyMCE will remove the
alt attribute if it is empty. Obviously, for accessibility and validation reasons, this is highly undesirable and needs correcting. Thankfully, the fix is pretty simple: add the following to your TinyMCE configuration options:
|// fix empty alt attributes|
|extended_valid_elements : 'img[src|alt=|title|class|id|style|height|width]',|
|verify_html : true,|
I choose to add these options right after declaring my cleanup/output options but before the remainder of the configuration. If you choose to tack these options on at the end, just remember to remove the trailing comma.