what is Promotional and Feature graphic in Android Market/Play Store?

Question

In market client on phones at least featured apps with high ratings get to display the promotional graphic.

This is the one that shows up on top even before you start searching the market for a specific app.

See this answer from Android market forum.

Edited: One of the google employee gives some clarifications here

Update: Both links above are now broken but the detailed information can be found here

Selected applications have the ability to be featured atop their respective categories. This is not a guaranteed feature, but uploading promotional graphics is something that we recommend.

I know there were several perfect answers but I found this page useful as well !

from: https://support.google.com/googleplay/android-developer/answer/113469?hl=en

Quote from the site:

The Feature Graphic is used for promotions on Google Play. While this graphic is not required to save and publish your Store Listing, it is required in order to be featured on Google Play.

Commentary:

To be clear, these "promotions" are chosen at Google's discretion. Even though excellent the "This is a test" app demonstration (above) shows the Feature graphic used in common areas of the outdated "Android Market", this is no longer the case with today's "Play Store".

Quote from the site:

The Promo Graphic is used for promotions on older versions of the Android OS (earlier than 4.0). This image is not required to save and publish your Store Listing.

Commentary:

It appears that this is also at Google's discretion and not always used as the "This is a test" demo suggests. Even though an older device may not get an update to their Android version, the "Android Market" update bringing them to a modern version of "Play Store" should be available.

I found this nice write-up that clears it up pretty nicely:

The different graphic assets we request are used to highlight and promote your application in Android Market, and possibly other Google-owned properties. If you’d like to restrict the marketing of your app to just Android Market, you have the option of opting-out of marketing by selecting the "Marketing Opt-Out" in the Developer Console.

Screenshots (Required):
We require 2 screenshots.
Use: Displayed on the details page for your application in Android Market.
You may upload up to 8 screenshots.
Specs: 320w x 480h, 480w x 800h, or 480w x 854h; 24 bit PNG or JPEG (no alpha) Full bleed, no border in art.
Tips:
Landscape thumbnails are cropped, but we preserve the image’s full size and aspect ratio if the user opens it up on market client.
High Resolution Application Icon (Required):
Use: In various locations in Android Market.
Does not replace your launcher icon.
Specs: 512x512, 32-bit PNG with alpha; Max size of 1024KB.
Tips:
This does not replace your launcher icon, but should be a higher-fidelity, higher-resolution version of your application icon.
Same safe-frame as current launcher guidelines, just scaled up:
Full Asset: 512 x 512 px.
Circle or non-square icons: 426 x 426 px, centered within the PNG.
Square Icons: 398 x 398 px.
Drop shadow: black, 75% opaque, 90 degrees down, distance of 14px, size of 36px.
Tweak as necessary to fit icon style (e.g., Google Maps icon has a drop shadow of varying height).
Promotional Graphic (Optional):
Use: In various locations in Android Market.
Specs: 180w x 120h, 24 bit PNG or JPEG (no alpha), Full bleed, no border in art.
Feature Graphic (Optional):
Use: The featured section in Android Market. Will be downsized to mini or micro.
Specs: 1024w x 500h, 24 bit PNG or JPEG (no alpha) with no transparency
Tips:
Use a safe frame of 924x400 (50 pixel of safe padding on each side). All the important content of the graphic should be within this safe frame. Pixels outside of this safe frame may be cropped for stylistic purposes.
If incorporating text, use large font sizes, and keep the graphic simple, as this graphic may be scaled down from its original size.
This graphic may be displayed alone without the app icon.
Video Link (Optional):
Specs: Enter the URL to a YouTube video showcasing your app.
Tip:
Short videos (30 seconds - 2 minutes) highlighting the top features of your app work best.

Featured graphics guidelines:

http://android-developers.blogspot.cz/2011/10/android-market-featured-image.html

List of graphics assets for your application:

http://support.google.com/googleplay/android-developer/bin/answer.py?hl=en&answer=1078870

You could also check our blog post summarizing all graphical assets for both Android and iOS:

http://www.skoumal.net/en/how-to-prepare-graphical-design-for-mobile-app/