OSD + overlays don't really work

[iafisher]

Here are some of the issues I've found:

• Overlays don't load until you pan or zoom in the canvas (one)
• Canvas doesn't automatically zoom out when all images are loaded (one, two, three, four, five)
• Overlays display as "undefined" (most of the images in this bundle, and this one as well, this image)
• Overlays never load (one, two, three)

As a matter of fact, just browsing through the images at random I was not able to find a single one that worked completely correctly.