Hi, you load pictures on them either from a PC, a memory card or flash drive. Some frames have built in memory which will hold pictures in the internal memory others just take them from the card you put in. I have just bought a Phillips one for my parents which holds over 500 pictures in it's internal memory and takes a number of different cards. Most work from the mains and will scroll through the pictures in order or random so that you get to see a different picture every few seconds to every day or so depending on how you set it. Some are very cheap but have a low resolution so the quality of what you see will not be as good as the higher resolution ones. Some of the bigger stores have them out on show so you get an idea on how they work before you buy. Just go in and press some buttons on them, I did.