Answer:
I am going to take a guess that "the three drawable folders" are drawable-ldpi, drawable-mdpi, and drawable-hdpi. In that case, if you stick with all of those folders, you need to put one image in each, sized to match the indicated screen density. This is discussed in the online documentation as well as this blog post. You can find a set of sample projects showing use of different drawable resources based on screen density here.
l hope it's help
