Have a look at the following verse which are words of Lord Shiva.
Agnou Tishtathi ViprAnam Hrudi Devo ManishinAm |
PratimAswapravuddhAnAm Sarvatra ViditAtmanAm ||
......
For the brahmins God resides in fire, for the manishi (or
mahatma) God resides in his heart, for the unintelligent he resides
in idols but for the self-realized he resides everywhere.
KulArnava Tantram 9-44.
So, it actually depends. If someone thinks he has successfully enclosed God in a small piece of paper, he can think of, putting that paper in some dirty places, like the streets, as an insult to him. But in truth none have the power to insult God like that, because he resides everywhere including even on the streets which apparently look dirty.
But, having said that, such behavior is not expected from persons who love God even a bit.
Any things related to him (like his images, nirmalayas etc) are ideally best disposed by immersing them in flowing rivers like the Ganges.