Android: Why create specific images for ldpi, mdpi and hdpi?

Question

I'm currently trying to support a larger range of devices with my Android app. However, even after reading through what the Android Dev Guide has to say on the issue, I'm unsure as to why I should provide different graphics for ldpi, mdpi and hdpi.

I understand that the images will automatically be scaled, so I can just supply hdpi graphics and let the device do the rest. Will the scaling quality be lower if the device does it? Will it be a performance issue? Right now I'm more worried about multiplying APK size by three.

Answer 1

I can think of two reasons:

1. Developer concern: Putting all icon versions in your package consumes space and bandwidth, scaling them on the fly consumes CPU. No prize for guessing which one is cheaper on a mobile device. (I suspect though that applications on the Android market will only download the applicable resources - in which case your users aren't even paying the space/bandwidth tax) Reference needed.
2. A designer concern: when you scale down an icon manually, you can (and a devoted designer will insist to) redesign the icon in order to get crisper results than automatic scaling. Look at this page for a detailed explanation of why manually scaling icons is good. (He talks mainly about iPhone icons, but that applies to Android icons as well.)