Taking photos on iPhone to appear on another iPhone's photo stream?

I'm going on holiday and don't want to take my iPhone 5c as it might get damaged/lost etc. So I want to take my old iPhone 4 just to take pictures on it. I was just wondering if there was anyway so when I take a photo is automatically appears on my iPhone 5c's photo stream back home?

(This is just incase I lost my old photo - which wouldn't matter too much since it is extremely slow)

Make sure both are signed into the same Apple ID & both have their Photo Streams enabled.

You can do that, just have both signed in on icloud with the same ID and you can also use Wi-Fi free. Something to think about though, the iphone 4 is still worth a fair amount of money today, but that will go down alot when the next iphone is released as 4 is several years old. I wouldn't just hang out to it, you should sell it or trade it in as it doesn't make sense to just keep it and not get anything out of it. 5C also has a superior camera to 4.