Hello,
I was fascinated by the fact that you have developed a userscript such as this, since I have about 3K images to deal with.
The problem I encountered is that I installed the script in my Firefox browser and nothing happened.
I am logged out of Dropbox and the target folder is publicly shared according to Dropbox parameters.
My browser is Firefox Windows MSIX package - 1.0, 131.0 (64 bits), working in Windows 11 Pro, v. 23H2.
The Dropbox link I used for tests is
https://www.dropbox.com/scl/fo/i3qwc2y2n6wzy7gp4oh4w/ABAjTcgkjRJ_rdyB9tx9OlA?rlkey=x71jfp52sp1qoeomfftdju8sr&e=2&st=j9yhk24u&dl=0
Opening the script, there were some warnings:

Again, thank you for your efforts, and I hope this note has been useful to you.
Hello,
I was fascinated by the fact that you have developed a userscript such as this, since I have about 3K images to deal with.
The problem I encountered is that I installed the script in my Firefox browser and nothing happened.
I am logged out of Dropbox and the target folder is publicly shared according to Dropbox parameters.
My browser is Firefox Windows MSIX package - 1.0, 131.0 (64 bits), working in Windows 11 Pro, v. 23H2.
The Dropbox link I used for tests is
https://www.dropbox.com/scl/fo/i3qwc2y2n6wzy7gp4oh4w/ABAjTcgkjRJ_rdyB9tx9OlA?rlkey=x71jfp52sp1qoeomfftdju8sr&e=2&st=j9yhk24u&dl=0
Opening the script, there were some warnings:

Again, thank you for your efforts, and I hope this note has been useful to you.