An easy way is to use iTunes. I set iTunes to manually synch as the "mother" PC is also used by grandchildren with iPads. In iTunes, Preferences, Devices ,tick the box "Prevent iPods, Ipads etc from auto synch".Then I would make a folder with the photos you want to transfer to the iPad on your windows PC. I actually have a folder also used for a photo frame. I redeuce the resolution from my normal 300 dpi used for printing, to 72 dpi as this is the max resolution for screens. It may be the iPad does this last automatically but I am not sure, but my method ensures that the pictures do not take up too much space. Then connect the iPad with iTunes open. On the photos tab, which should then appear, browse to find the folder you want and synch it.I actually do the music and films in a similar way as my grandchildren have different tastes .
iPhone X review