1. Download Sim4pe here
2. Open the file of the painting you want to change. There will be a list of items, and when you click on them an image will appear to the right.
3. The charts I've made will show you which new painting replaces which EA/Maxis painting.
4. Find the one you want to change in the list in Sim4pe. Highlight it, and hit delete on your keyboard. You can also right-click on the item and choose "deleted" from the menu.
5. Save the file, and exit Sim4pe. When you run the Sims 4, the painting will be back to its original design.

1. Follow steps 1-3 above
2. Find the painting you want to change in the list in Sim4pe. Right-click on it, and choose "Export/Import via Helper" from the menu.
3. A small window will pop up. Click on "Export", then give your image file a name and save it.
4. The image files are saved in .dds format. To modify .dds files you will need a plugin, which can be found here and a program like Photoshop or Gimp.
5. Open the image file and paste the new painting in. Save the file. A .dds file save options window will pop up. Choose "DXT5" from the dropdown menu, and leave the rest of the options the same. If this menu does not appear, try using "Save-as" instead of "Save".
6. Back in Sim4pe, right-click on the painting again, and choose "Export/Import via Helper" again from the menu.
7. A small window will pop up. Click on "Import", then find your new image file a name and open it. Click "Save and Close"
8. Your image should now appear in Sim4pe. Save the file and close. When you run the Sims 4, the painting will be your new design.