It deepends on how respectful it is treatet. Don't put it on the dirty ground, don't step on it or use it as a towel. Don't let people throw tomatoes on it.
To make an artwork with buddhistic images is a karmic wonderful act. It puts a very good impact on your mind.
And even better than to throw such images into the waste it is to burn them.
If you work with it, the Dharma will talk to you and show you also many facts about yourself. A wonderful and maybe important work for yourself.
Metta, Karuna, Mudita, Upekha
*** May these efforts be helpful.
Djang chub sem chog rinpoche, ma kye pa nam kye gyur chig. Kye pa nyam pa me pa yang, gong nä gong du phel war sho._()_**