The cigen.package Thumbnail Cache
This file contains thumbnail images for items that have been displayed in Body Shop. That is, Body Shop only creates thumbnails for items as they are scrolled into view. If this file is deleted, Body Shop will recreate it and add thumbnails as needed.
The file contains three types of resource
- 0x43524944 - unknown to SimPe, 16 bytes. Purpose unknown.
- 0x43494745 - unknown to SimPe, variable length. This is a lookup table mapping resource keys to thumbnail keys, see classes Cgn1 and Cgn1Item in my DbpfLibrary for more details.
- 0x856DDBAC - jpg/tga/png Image, variable length. The cached thumbnail. Maxis modified jpeg including the alpha channel (stored in the ALFA block in an unknown format). Note, the Maxis modification has technically broken the JFIF standard, but most jpeg reading code can cope with the broken format.
To locate a thumbnail, get the key resource (AGED, GZPS, XMOL, XTOL) for the item and use it to lookup the associated thumbnail resource. Note, there may be zero, one or many thumbnails for an item.
So long as the primary resource (GZPS, XTOL, XMIL, AGED) group and instance ID of a Body Shop item isn't changed, the other values (sort, category, life stage, gender, et al) are irrelevant for locating the thumbnail, as is it's location on the disk.
Hope these notes are of use to someone. Enjoy!