title: Cross origin problems getting base64 encoding of an image
body: <p>I am making a "simple" bookmarklet for 4chan (potentially extensible to other sites) that will download all images in the current thread as a zip archive. The images displayed in a 4chan thread are just thumbnails. The images themselves are provided as links that can be accessed by clicking the thumbnails. </p>
  
  <p>My code should work almost perfectly. I found the class that contains the links to the full-sized images. I select all of these 's with jquery. I am using JSZip to compile the images. But JSZip requires the image data encoded in base64. After scourging SO for methods to do this, it seems almost unanimous that drawing an image onto a canvas and converting the image to base64 that way is the best way to do it. However, since 4chan provides links to its images instead of them being right there in the site, the canvas becomes "tainted" when I draw a linked image onto it, and I cannot get the base64 encoding from it. </p>
  
  <p>How can I do this differently so that it works? Is there a way around the cross origin thing? I tried adding <code>crossorigin="anonymous"</code> to the images I'm creating, but it doesn't work.</p>