It's possible, but I would recommend it only if you are quite confortable using Sims4Studio to edit your savefile. There might be bugs doing it, so I prefer to warn people before.
- Open your save in Sims 4 Stuidio
- In the filter box, type "Texture" to display only the custom textures in your save. That will include all the photographs, the paintings from reference, and the custom furs. Click on the File Size column header to sort items by size: it will be easier to find duplicates as they have the same size.
- To delete an unnecessary item, just click on it and click on Delete at the bottom.
The tricky part is to detect which texture is used in case you have multiple duplicates:
- Open your save in Sims 4 Stuidio
- Filtrer by "Save Game Data" to find the main informations about your save and click on it.
- In the right panel, scroll until the end until you find the line "sims". Click on Edit items on the right of it.
- A window will display all the Sims in your save. Find the Sim(s) and/or the pet(s) using a custom fur, and click on them.
- Filter the right panel by "custom_texture". If the Sim/pet use a custom fur, you will have an id displayed at the right of this "custom_texture" (if it's not the case, you will have "0000000000000000"). Copy and paste those ID somewhere where you can list them (ideally with the Sims they belong to).
- I would recommence closing Sims 4 Studio without saving before opening it again to delete textures (i experimented that opening the sims info would cause some issue if you save after).
- Reopen your save on the Studio, and as described above, when you find a texture with multiple duplicates, you can identify the one that is used: it's instance will be the same as the id your retrieved before. You can keep this texture and delete the rest.
I hope that helps.
It would be better if the game automatically cleaned up unused textures on sims, pets and objects but here we are. Maybe a utility can be created to identify textures that are not tied to a sim/pet/object ?
