I've just modified my copy of meta.php to include FastStone Image Viewer's Comment (which is stored as a file comment, not Exif).
Just wondered if it's possible to include this in later releases?
Here's my additions:
Around line 150, before the ...WINXP.. test:
//3sep11 ebraatv: Use FastStone's comments if found
if ( isset($this->exif_data['COMMENT']))
$meta['caption'] = utf8_encode($this->exif_data['COMMENT']);
I also removed the duplication of title as description if you use Properties in Windows to modify XMP data, around line 270:
//3sep11 ebraatv: Do not use windows' duplicated title as caption...
if ($xmlarray[$key] != $xmlarray['dc:title'])
$this->xmp_array[$value] = $xmlarray[$key];