Image size returned by g->image

When viewing my android device the g->image tag returns a smaller image size (not even available in the album setup) that what it returns when viewing with my desktop. If I set my desktop to report the same user agent as android, I still get the larger image. If I go to the slideshow (version 1.0.5.1) page for the same image, I get the larger 640x... images. Is there something that causes g->image to return a smaller size based on user agent, or detected screen resolution or size? Here's a page from my site http://photos.netbymatt.com/2010/riverwalk/IMG_9814.JPG.html

Thanks

Gallery version = 2.2.4 core 1.2.0.6
PHP version = 5.2.8 cgi-fcgi
Webserver = Apache
Database = mysql 5.0.91-log, lock.system=flock
Toolkits = Exif, ImageMagick
Acceleration = full/604800, full/604800
Operating system = Linux linhost294.prod.mesa1.secureserver.net 2.4.21-63.ELsmp #1 SMP Tue Nov 3 18:23:59 EST 2009 i686
Default theme = greymatter
gettext = enabled
Locale = en_US
Browser = Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv:1.9.2.8) Gecko/20100722 Firefox/3.6.8
Rows in GalleryAccessMap table = 573
Rows in GalleryAccessSubscriberMap table = 4243
Rows in GalleryUser table = 2
Rows in GalleryItem table = 4242
Rows in GalleryAlbumItem table = 188
Rows in GalleryCacheMap table = 80

Matrix doesn't show anything in the album. Carbon shows the smaller image (max 300px) like my custom theme. I'm thinking it might be something I did with an older "mobile" theme that I used to run. I'll have to track it down, that was a few years ago. Any suggestions on where to look, since it seems to be a global change?