We now have better, user-friendlier display for apps and libraries:

http://blog.stackoverflow.com/2011/02/stack-exchange-api-1-1-and-improved-app-gallery/

We infer a number of things about the app or library, but we also offer the following overrides for tweaking the listing to get it "just right":

    <!-- thumbnail: http://example.com/thumb.png -->
    <!-- tag: iphone -->
    <!-- version: v1.0 -->
    <!-- excerpt: This text will appear in the listing -->

However, **since the thumbnails are featured prominently on the home page, it's important that they be properly chosen, particularly for applications (not so much for libraries)**. We want app thumbnails to have the following characteristics:

1. Be cropped down to a reasonably small size, so they are legible at ~144 x 91 res.
2. Show the user a hint of what the application *will do*.
3. Don't show a generic icon or logo, unless the generic logo communicates what the application does in a meaningful way.

(none of this really applies to libraries, though I think libraries would do well to include some visual cues to indicate of what platform / language they are for.)

Because thumbnails appear on the home page for all visitors, we want them to be exemplary -- and we reserve the right to exert editorial control over app thumbnails as necessary, to make sure that visitors to Stack Apps have a clear idea of what the applications are and do.