Recommended Android Market screenshot format

In the Android Developer Console you can upload the screenshots of your app (max 8 currently) in several sizes, like 320x480, 480x800, 480x854 and 1280x800.

But it turns out that sometimes (always?) if you upload in the higher resolutions (like 480x800), the images get cropped in a weird way in the market on your phone (at least the Nexus One). The images will look fine in the online Android market, but not on a physical device. Actually, when you look closely, the dev-console gives a thumbnail of the screenshots and there you can already see that the images are cropped strangely sometimes; like the left 20-50 pixels just cut off. And that's actually how they also appear in the market on devices!
After some experimenting, it turns out this does not happen when you upload in 320x480 format.
Thus the recommended resolution to upload screenshots seems to be 320x480! Doesn't matter if you use a device (like the Galaxy S2) or emulator to take the screenshots.

Note I didnt check if the browser market image quality decreased when going from 480x800 to 320x480. Though clicking on an image in the webmarket shows the 320x480 uploaded image quite fine.