Tell if screen is original or replacement on iPhone 5 I recently bought a iPhone 5 on eBay. Now I'm suspicious if the screen is the original one or a replacement.
Is there a way I can clarify my concernings?

The screen has problems to recognize my touches and sometimes doesn't work at all.

Here are a few pics of the "suspicious-looking" Screen 





You can see the different colors on the screen AFTER I cleaned the whole screen with a special display cleaner.

Can someone explain this ?
I am not sure what those marks you are showing are, but I am slightly concerned by the colour of the proximity sensor on the left of the ear piece in photo 1... 

Have a look at my previous answer to a similar question:
How to check if the screen replacement part for iPhone 5s is an original one?

This might help also.