Yes, using the Shiba Media Library plugin mentioned above. However, while I managed to make it work, I am still not sure about the long term trade-offs.
Essentially the Shiba Media Library plugin enables you to deattach an image from a post and attach it to another. I had Media Library images already attached to pages, which I subsequently wanted to include in a gallery of software application screen shots. I didn't want to upload the same screen shot again. www.recollx.com
What I did was detach the image from the original page and then attach it to the image gallery page. By resaving the Juicebox gallery settings, the XML gets updated with the newly attached image. While the image remains in the original page, as far as I'm aware it is no longer linked to the Media Library. This may mean that updates to descriptions in the media library will not propagate automatically to the original page where the original image remains.
Still being new to WordPress, I have to confirm if that is in fact the way Media Library works... i.e. does updating the image info, such as a caption, in the media library automatically update what is shown on a page which already has that image attached? I'll have to test.