Shrink-to-fit larger image

Ok I'm not sure if this really counts as a feature request or bug report... Anyhow when viewing the larger image in firefox (the most popular browser since 2009) the image shows at full size rather than shrinking to fit as it does in explorer.

If this feature could be added to (or bug fixed for) the site (for those using firefox), then the site as a whole would be unbeatable!