Photos app on iPhone 4 has no search(looking glass)

I'm not sure this is the right place to ask the question, however, just curious why I can't find the looking glass or search on my wife Photos app,, like I have the capability on my own iPhone 6 plus. She has iOS 7.12 I think, and the Photos app because we have the latest iTunes.

I'm just curious whether other people with iPhone 4 , and same IOS, could see that search function. She has the latest OS on Mac Yosemite also.

For her the search function is invaluable, because she has difficulty with the Photos app itself, compared to the old iPhoto, and her navigation of the Photos app is very poor (seems like she isn't the only one).

Thanks for helping me solve this mystery. I suspect that the age of phone, and older IOS software (which can't upgrade to iOS 8)might be the problem, however, with most of the other elements up to date, I thought there might be a chance I was overlooking something else. Thanks