title: Android Resources - which resolutions should go into the hdpi, ldpi, mdpi and xhdpi directories
body: <p>I'm trying to write an application that will work well on all screen sizes, for that I have my graphic designer produce images that are in the requested dpis for each directory (Low density (120), ldpi, Medium density (160), mdpi, High density (240), hdpi, Extra high density (320), xhdpi) however, they want to know at which resolution and aspect ratio each image should be, after looking around the android documenation, namely:
  1)http://developer.android.com/guide/topics/resources/providing-resources.html#AlternativeResources
  2)http://developer.android.com/guide/practices/screens_support.html
  I came up with the following information:
  It is not exact that android supports 3 screen sizes, android is an OS that can run virtually on any screen size but there are some screen sizes that are more common than others, these are demonstrated in the table below (taken from <a href="http://developer.android.com/guide/practices/screens_support.html" rel="nofollow">http://developer.android.com/guide/practices/screens_support.html</a>)</p>
  
  <p>Table 1. Screen sizes and densities of emulator skins included in the Android SDK.
      Low density (120), ldpi     Medium density (160), mdpi  High density (240), hdpi    Extra high density (320), xhdpi 
  Small screen    QVGA (240x320)<br>
  Normal screen   WQVGA400 (240x400)
  WQVGA432 (240x432)  HVGA (320x480)  WVGA800 (480x800)
  WVGA854 (480x854)<br>
  Large screen        WVGA800* (480x800)
  WVGA854* (480x854)<br>
  Extra Large screen  </p>
  
  <p>It’s worth noting here that even though it seems that there is no correlation between these screen sizes, there is a 3:4:6 scaling ratio between the three densities, so a 9x9 bitmap in ldpi is 12x12 in mdpi and 18x18 in hdpi (see <a href="http://developer.android.com/guide/topics/resources/providing-resources.html#AlternativeResources" rel="nofollow">http://developer.android.com/guide/topics/resources/providing-resources.html#AlternativeResources</a>).</p>
  
  <p>We can see some more information on what the screen sizes mean here:</p>
  
  <p>Screen size 
  •   small: Screens based on the space available on a low-density QVGA screen. Considering a portrait HVGA display, this has the same available width but less height—it is 3:4 vs. HVGA's 2:3 aspect ratio. Examples are QVGA low density and VGA high density.
  •   normal: Screens based on the traditional medium-density HVGA screen. A screen is considered to be normal if it is at least this size (independent of density) and not larger. Examples of such screens a WQVGA low density, HVGA medium density, WVGA high density.
  •   large: Screens based on the space available on a medium-density VGA screen. Such a screen has significantly more available space in both width and height than an HVGA display. Examples are VGA and WVGA medium density screens.
  •   xlarge: Screens that are considerably larger than the traditional medium-density HVGA screen. In most cases, devices with extra large screens would be too large to carry in a pocket and would most likely be tablet-style devices. Added in API Level 9.</p>
  
  <p>We can also support specific aspect ratios, as defined here:</p>
  
  <p>Screen aspect 
  •   long: Long screens, such as WQVGA, WVGA, FWVGA
  •   notlong: Not long screens, such as QVGA, HVGA, and VGA</p>
  
  <p>--
  All of this however, is not enough to answer the simple question of what the resolution should be on those images - can they all be cut from the same high res image or should they be re-done for each dpi since the aspect ratio is different?
  please help, this is holding up my project
  Thanks!</p>