From experience, go with one of the top name brands, the others I have experience with all seem to be liable to overheat, slow running and "bits flaking".
I personally have a samsung, and find it ideal for everything, but opinion varies and my mate says he couldn't possibly be parted from his ipad. each to their own I guess.
With Samsung you can add a micro sd card for extra space for your photos, where the apple product will require a subsciption to their cloud once you've used all the ipad internal storage.
Samsung are also considerably cheaper, but quality of both is comparable.
Perhaps a currys/pcworld visit to see which she prefers would be the best option. (I have no experience of miscrosoft tablets, although they do look quite versatile).