We can create image maps as normal when doing /image2map create, but when we do /image2map preview, we see "Getting image...", and players aren't sent to the area where they can edit the image. This means that we can't resize our images.

any updates on this?

Nope, unfortunately still an issue for me.

Something interesting I found out: after turning off and restarting the server, doing "/image2map preview" works once, sending you to the area where you can edit the image. However, once you're there, you can't resize it. And after you exit, doing "/image2map preview" just shows "Getting image..." and nothing happens.