I checked out :
http://www.peak.ne.jp/xoops/modules/xhnewbb/viewtopic.php?topic_id=294&forum=2
and found the solution.
Bascially, if you get this problem when batch registering photos in MyAlbum-P, you need to do a 'rebuild thumbnails' routine to get the photos the right size.
In the MyAlbum-P admin, click on 'rebuild thumbnails' select the 'resize bigger photos than the pixels specified in current preferences' option and click the 'next' button.
If you want to process more than 10 images at a time, change the default 10 to a higher number. It's good to start at record 0 or 1 and work your way up to process all the photos in increments. the record number will update automatically after each batch edit.
hope it helps,
happy XOOPing