Full documentation can be found on the Thumbnail for Excerpts page.
Open the PHP file and edit as you wish. Here are the constants and theri explanation
define("TFE_ALIGN","left"); can be left or right
define("TFE_SIZE","100"); the size of the thumbnail; modify it for better integration with your design; if you set it as 0 it will be than the default size of your WP thumbnails, from admin area
define("TFE_MAXSIZE","no"); if yes, than the above indicated size will be used as maximum size for widht and height; if no, than the above indicated size is used only to limit the width
define("TFE_SPACE","5"); for the HSPACE parameter of the IMG tag
define("TFE_LINK","yes"); can be yes or no; if yes, the image will link to the post
define("TFE_CLASS","imgtfe"); the class for the thumbnail images; you can change it or use this class in you CSS file
define("TFECREATETH","no"); if yes, the images without thumbnails will have one created now (based on default values for thumbnail from admin area, or on TFESIZE if in admin area thumbanil size is set to zero)
define("TFE_TITLE","no"); if yes, it will use titles for pictures (when you move mouse over the picture you will see the alt text)
1.3 [November 22, 2008] - working now with GIF and PNG also - working now also with WordPress installations which do not use wp_ for tables - tested for WP 2.7
1.2 [September 9, 2008] - can create thumbnails if do not exists
1.1 [September 6, 2008] - some suggestion implemented (link, title, max dim)
1.0 [August 13, 2008] - first release




