Screenshots to upload my app?

I want to make 2 quick screenshots for the app am putting in the market.. But problem is when i signed the app for the market i can't transtef it to my phone and install the开发者_如何学编程 .apk.. Its not working..

Am using Eclipse. And i can't realy find a way to like make it an .apk that i can install from the phone cus the signed apk seems to not work..

Is there some other way i need to do so i can install this apk ? And when i signed the app what do i need the certificate for?? When uploading it doesn't say anything about i need it..

Thanks if you can help.

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It sounds like you're not signing your application correctly. Have you tried reading this? It's very helpful: http://developer.android.com/guide/publishing/app-signing.html

Also, you should be able to just run the application on your phone from Eclipse and take your screenshots using Android SDK's built-in screenshot functionality from the Devices view.