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What dimensions should be used for application icons displayed on the BlackBerry® Tablet OS home screen?
Application icons, used for display on the BlackBerry Tablet OS home screen, should be 86 x 86 in size and be of type PNG.
For more info about application icons, including best practices, see the "Designing application icons" development guide.
If only PNG is acceptable, why does this page say (as of 2011 Apr 13) that JPG is an option as well?