Widget 4x2 - appwidget-provider minWidth and minHeight for all resolution

I'm working on a 4x2 Widget size, and I wonder about my appwidget-provider declaration, I want this widget works for hdpi - ldpi - mdpi screen :

<appwidget-provider xmlns:android="http://schemas.android.com/apk/res/android"
android:minWidth="294dp"
android:minHeight="144dp"
android:initialLayout="@layout/widget_message"
android:configure="fr.cdcorp.homewidget.configurationActivity.WDWidgetConfiguration"
android:updatePeriodMillis="43200000" 
/>

1. Are these settings (android:minWidth="294dp" andandroid:minHeight="144dp" ) good for ldpi and mdpi?
2. Do 开发者_运维问答I need to detect screen size and set up programaticaly a different minWidth and minHeight for medium and lowscreen size?
3. The layout I use for it is a background image which is 294px x 144px -16bit, do I need to have lower resolution in drawable-hdpi, drawable-mdpi, drawable-ldpi?
4. Furthermore, I need to change programmaticaly image background, so do I need to test screen size and put the correct image for it?

Thanks for answers ! Christophe.