Decrease the minimum size of the click box.
The clickable pictures allow you to re-size the box that indicates the correct region. However, the box has a minimum size that is too large for some applications.
Sometimes it is necessary to define a very small region if you want the audience to identify a very precise finding. Ideally there would be no minimum box area, or it would be not much larger than a persons finger on a tablet. A 300 X 300 pixel box would be a good size for a small box if the pictures was full screen on a 2048x1536 pixel iPad. The box could be even smaller if the poll is meant for computer useres with mouses.
I see the argument for a minimum box size. That small box would be too small to accurately click when the image is scaled down to smartphone size. However, this feature would still be very useful for presentations like mine, which are image-rich and the audience must bring a high resolution tablet or computer.
Good news! Smaller regions can now be created. We will flash up a warning if it looks like your region will be hard to hit on some devices, but you can chose to ignore this if your use case suits it.
scott erickson commented
Can you make the region of interest for clickable images more scalable? For instance, I need to define smaller areas to delimit small anatomical structures. Otherwise, you have created a wonderful product.