In the help thread some (including me) complained about not getting icons (or wrong ones) in the buy-catalog. I researched a litte.

It seems to me those icons are generated when sims2 first encounters a new object (identified by it's GUID, I think).

Now, when we change our selfmade object, it's GUID isn't changed and therefore Sims2 sees no need to update the icon.

What can we do? Easy! Open up SimPE and navigate to "my documents\EAGames\Sims2\Thumbnails". There you find a file named ObjectThumbnails.package, open it.

In the "Filetypes"-window click onto "thumbnails".

In the "Packed Files" - list now all thumbnails are listed, a lot of them. Klick onto "offset", to sort them by offset in the package file, since new generated icons are most likely appended at the end of the file. Now choose the tab plugin view and click through the entries starting at the thumbnail at the END of the list. It is most likely that you will find empty thumbs or otherwise wrong ones easy that way. Now just delete them and they will be generated new at the next time you start sims2. (if you do not trust me, you can of course save them before deleting by right-clicking and exporting, grin)

Have fun! :D

This was also a problem with recolors. You could delete the whole thing and the game should regenerate all of them. (though, do make a backup in case I am mistaken)

Thanks, Xanathon, this is a really smart advice! When I had trouble with the thumbnails, I always deleted the entire package (the game rebuilds it, as said by trombones). But SimPE's Object Workshop relies on thumbnails to create the list of the recolourable objects, and so I had to rebuild the whole thumbnails database by browsing *all* the items in the catalog, including the "build" ones!
Now I can simply delete the last ones added to the thumbnail package.

There is a copy of the entire default thumbnails package (all of them) in the game install directory. Instead of deleting, it's much better to just copy that one overtop of the old one.
Then, all that has to be created by the game is the new custom ones.
As one extra note, I often have blank icons because I forgot something the first time I tried to test, got a blank one, and the game won't change it unless you A> change the GUID or B> change the filename.
<* Wes *>

Wow! Two good advices for the price of one! I also used to delete the file and then had to browse through the catalog. Now I'm going to try to just copy the default one on top. Thanks!