Hi! I use this app for all my drawings now a-days, and I have some ideas for the reference panel.
As fine as it is, it could be wonderful to toggle the option to make the panel background invisible, so you can see the canvas underneath the zoomed out photo.
Also, another option that could be added is to lock the rotation of the image, so that zooming in doesn't lead to making it unaligned.
Adding onto the prior suggestions would be the addition to either open multiple images into one panel, or opening multiple reference panels to have different references at once.
Thanks to anybody who reads this!