Steps to reproduce:
1. Start a new project
2. Create a object and assign a material to it.
3. Add any image texture node.
4. Don't connect it to any input.
5. Launch render.... it takes few seconds longer (depends on texture file size and it's quantity) then without any texture.
6. In systems users folder a liveDB folder is created with texture that has been used in any project. (this grows to GIGABYTES size!)