I\'ve been through this post (and others) as well as through the documentation about supporting different screen resolutions in Android, but I couldn\'t find a clear answer to a
The images in the drawables folder are assumed to be at mdpi resolution, so they will get scaled up/down if you don't provide the others.
Scaled up images will be low-resolution and look fuzzy. Scaled down images will have pixels missing and look jaggy.
So your app will "work" with only one set of default images, but will look awful on many devices. I strongly advise that you create the images in different sizes, so it looks great on all devices - it's a bit boring, but not hard to do.
It won't be long before we have xhdpi devices, so while you're at it you may want to create those too.
I assume you've read this