How to convert zip file to apk file ?

[Android Question]

I downloaded a apk file & decompiled it by using decompileandroid.com .I got a zip file extracted the contents & modified one jpg file in res>drawable folder. Then i compressed it to zip file. How should i convert it into apk file ?
I think the problem is with the signing process. I have no META INF folder in the app,but i don't know how to get it.I don't know how to use jar signer. I am a newbie to android so please help me.

 

[scary alien]

I'd suggest using apktool since it will recompile and re-package the .apk for you with it's simple command line interface.

Check out the link above (and also search for other reference resources re. apktool on the web and you'll do fine ).

Cheers!