venbury - the best way is to use Sims2Pack Clean Installer to extract the files to a temporary folder, then use SimPE to scour the files for text that names the creator. Since not all artists do this, it is not always possible to give proper credit, so tag those items as "unsigned artist" and when able include the text the artist inserted so : "my weird eyeshadow" by unsigned artist
alternately you can make a screencap of the S2PCI content viewer :

originally posted by Ms Simbodies
Just do the best you can, if anyone bitches tell me and I will deal with it.