iTunes ConnectからWaiting For Upload状態に設定して、
We have discovered one or more issues with your recent delivery for "__App Name__". Your delivery was successful, but you may wish to correct the following issues in your next delivery:
Invalid Image - For iOS applications, icons included in the binary submission must be in the PNG format.
If your application supports the iPhone device family, you must include square icons of the following dimensions: 57x57 pixels and 120x120 pixels.
If your application supports the iPad device family, you must include square icons of the following dimensions: 72x72 pixels, 76x76 pixels and 152x152 pixels
For Mac OS X applications, icons included in the binary submission must be in the ICNS format and must include a square 512x512@2x image.
If you would like to update your binary for this app, you can reject this binary from the Binary Details page in iTunes Connect. Note that rejecting your binary will remove your app from the review queue and the review process will start over from the beginning when you resubmit your binary.
Yes, there are new icon sizes for iOS 7. See this article: New Metrics for iOS 7 App Icons. It explains (near the bottom of the article) the sizes you need for iPhone and iPad: