How do I get WP to use image filename for Title, and IPTC Desc for Description?

Hi,

I edit images in Photo Mechanic and Lightroom and for SEO purposes when I upload them to my WP site I want to make use of plugins that populate the WP ‘alt’ field by taking the contents of the WP ‘Description’ field and applying those to the ‘alt’.

This means I need to populate the WP Description field first, which I intended to do by filling in the IPTC Description field in the metadata for each image in Lightroom etc.

This would work, but WP is doing something weird. If there’s something in the IPTC Description field it hijacks it for the WP Title field, then doesn’t bother using it for the WP Description. Why?

The only way around this seems to be to populate the IPTC Headline *and* IPTC Description. In this case, WP uses the IPTC Headline as its Title, and the IPTC Description as its Description.

That works, but is still less than ideal because I already gave all my images good filenames in PM/LR, and would like WordPress to just use those for the Title. I have no need for WP to guess at a better Title, just use the name each image already has, without the extension.

Is this possible, without messing around with plugins?