AirPrint images are tiny when printed from iPad Air

Hi there. I've got an iPad Air and an iMac both networked with the same Canon PIXMA iP110 wirelessly. However, Airprints from Safari on the iPad Air have really tiny images (pictured on the left). I don't see anything in settings that would allow me to change this, so I'm totally stumped. Same page, same printer, different results.

Here's an example of what I'm trying to print: http://shop.fraichehome.net/webtexweddingregistry/index/registry/id/RZYDFYUHHZYG /

I have downloaded Canon's print app for iPad but I don't see anything in the settings; and anyway, I want to use AirPrint from Safari, not that app.

Any suggestions are appreciated. I do have control over the content and its print.css if you think that may be causing a problem.