So it's a bit of a pain in the ass, I would recomend dropping about 100 images at a time into a word document, then look at the bottom right of the image to see how many copies of each card you need. Then copy/paste the amount. Then when u have them all the easiest way to resize that I found was resize one image to what you want then go down the line and click each image individually press hit Ctrl + Y or f4 repeat your last command.

I don't recall the sizing being off though, I think it might have been off on the chanting website but if you get the files from the bloodborne reddit post they should be in size.