Rather than maintaining the belongings of each character on a sheet, the cards can be used to always know who owns what.
This facilitates trading objects between PCs, but also between PCs and NPCs.
If you replace the images directly in the image directory of the application, these changes may be overwritten with the next update.
You should instead create a file called imgrules.txt in the User directory, located in the installation directory that you choose for OpenDD.