Fix bug where image couldn't be found by card name.

- Previously it would try to find the card's source image by looking for
  an image tag with an alt name equal to the card name. This likely
  wasn't matching due to capitalization. Now we just look for a src tag
  with the words "scans" in it.
- Fix bug where test-images had nil image urls instead of the correct,
  expected ones.
- Remove testing cruft.