OS Catalina does not allow you to extend the list of 'safe files', so jaskin files need to be double clicked or drag and dropped onto jAlbum. Firefox lets you add jaskin files to the list to be opened on download, but it always asks you to confirm you want to do so.
The attached is an AppleScript that when attached to the Downloads folder, as a folder action, will install the skin into jAlbum and move the jaskin file to the Trash.
Instructions for adding the script:
Download the script and move it to (your Library) Library>Scripts>Folder Action Scripts.
In Finder's search field enter Kind: application folder actions setup
Open Folder Actions Setup
Ensure Enable Folder Actions is set
Click on the + below the Folders with actions and navigate to the Downloads Folder and click on Open.
Scroll to the bottom of the popup window and select the Open jaskin files.scrpt, then click on Attach.
Now, when you next download a jaskin file , in any browser that uses the Downloads folder, it will be installed and the downloaded file moved to the trash for you.
As usual, use at your own risk - test on my Mac only.
Modify as you like but keep the derived from Apple information.
Edited by: RobM on 02-May-2020 00:08
Fixed an oversight that caused jAlbum to open after downloading a non-skin file