iPhone: How to upload screenshot for in app purchase review?

I go to Manage Your In App Purchases, select the In App Purchase and when I click "Approve" I get this message:

The following error(s) occurred: * You must upload a screenshot before approving an In App Purchase开发者_JAVA百科

I can't find where can I upload the screenshot. Thanks for your help!

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You need to hit the Edit button at the top of the screen, then there is an "Upload File" available.