Interesting - first I'd submit a bug report just in case. Second, I would search for a similar image that isn't as big - you can drag and drop an image onto images.google.com to search similar images (I've had random times when an image ids being "weird" and I've searched another). Third, check out the references from W3Schools that might be of some help. If all that fails you could try to use CSS to style the image accordingly.
An additional option is to take a screenshot of the image and upload it, but make sure the students are still giving rights to the original image, screenshots can open up a can of worms in regards to intellectual property rights.
Let me know if you have any additional questions!