Should I get iphone 4 or 4s?

I'm upgrading my phone soon and I'm on a very strict budget so I'd rather not spend too much money. I like both phones but I'd like to know which phone is better. I don't use many apps or music what I would be using the phone for most (besides talking/texting) is the camera. How many pictures will an 8/16g hold? Also will pictures remain on the phones memory after they've been deleted? I mean if I have 100 and delete 10 can I still add another 10?

4s it has way more features

Get the iPod Touch 5G instead of iPhone 4. But iPhone 4S is also good.

I hate iPhones but I sold cell phones for years - hope my advice helps:

Differences:
iPhone 4:
-single core processor (vs dual core in 4s) // Note: this is a useless feature in both phones because they can't truly multitask
-weaker camera (5Megapixels vs 8 + high capture rate with 4S) / Note: if you love picture and video taking 4S will treat you better
- no Siri (vs 4S with Siri) / This is a voice command feature. Great little feature, not so use full if you have any kind of non-american accent whatsoever. (that include English and Australian accents)
- screen resolution is a little better in the 4S. If you are a normal person and are not glued to your phone 24/7 watching things that require ridiculous detail then this may not matter to you.

These are the only changes Apple made. I hope you iPhone users felt it was worth the extra 100 bucks to pay but 2 cents extra to make.

As for the picture question.iPhones don't have a secret memory bank that keeps all your deleted stuff. Once you delete it, its gone. Don't worry about it. 16GB or 32GB of memory in these phones is a lot if you don't do much on the phones. Trust me.

The analogy my friend uses is would you rather have an xbox or an xbox 360?

in my opinion its better to spend the extra 50 bucks and get a phone that lasts. I rock the 4s, and i rocked the 3gs back in the day.comparing my 3gs to a 3g, the 3g was a brick compared to the 3gs. I'm sure its the same for 4 vs 4s