This script is the last server step in rendering of an index.php file for a captions segment. (Where a "segment" is a section of a captions file beginning with a file: line.) See sample at left.

The header section sets in-memory properties for the contents of the top, sides, and bottom of the image. All are values taken from existing properties, namely thumbs.toprow, thumbs.leftcell, thumbs.rightcell, thumbs.trailer. These properties are interpreted by the PhyspicsMain template.

The body is wholly the contents of property thumbsparms.pictures, which in turn was generated by genhtml from the lines of the captions segment. In thumbsparms.php, that body is stored as the value of thumbsparm.pictures; it is this property that thumbs.php fetches and displays.

There is only one instance of thumbs.php; there are not even any files generated with it as a template. The actual page generated for a captions segment is an instance of thumbsparms.php (the value of property thumbs.template). It sets in-memory properties with names prefixed by "thumbparms." and finishes by including thumbs.php (which is the value of property thumbs.wholepage). This two-step approach is necessary because genhtml has its own ideas about how to treat dollar signs.