Why not use SD cards? - they're even more compact than USB memory sticks, and virtually indestructible. I usually buy mine from Picstop in the Isle of Man, who are very reasonably priced, and have given me good service. You can fit several cards in the smallest Jiffy Bag, and you only need the lowest read/write speed type, as it's just being used for storage, not fast transfers in a high spec camera. Most PC's now have a card reader built in, but if not they can be had for a few pounds. You can arrange your photos' into folders before copying them onto the card(s) so your recipient can transfer them directly onto her computer with the minimum hassle. At the moment there are more 32GB cards to choose from - the larger sizes are still rather pricey.
TFP