Ok, here is an upgrade to the script that allows to add a tattoo on a skin part.
It can be downloaded here: https://kdrive.digital-paradize.com/app/share/116364/2e44a808-24a2-42df-93de-1b73f5da482c

A new button has appeared: Setup, it displays a list of personal folders to add (they appear before Shana's). The Save button closes the part that overlaps the picture of the last selected tattoo, that part also disappears if one select another volume or content.

As you can see above, the complementary folders are stored in the script's config file:
- same place as other tools: in Poser's data folder,
- on Windows: in the user's profile, roaming part
- on Mac, if I'm not wrong in a place called Application data (?)

Actually, I don't know how to use a PNG with a transparent background, whatever the image node is used and whatever the way to add the necessary nodes.
Even with a Mix + Transparent Closures setup nodes, the result is not satisfying, at least with the PNG I have (see below).
I may have missed something. If a solution is found, the script will be updated consequently.

Example with another tattoo, as a JPG file from a PNG with a transparent background, replaced with a white background.

Note that the Laced Patterns entry is just to have two user-defined paths as it's mainly for clothes...
Also note the the Content list displays only JPG, JPEG and PNG files

𝒫𝒽𝓎𝓁

---

(っ◔◡◔)っ

👿 Win11 on i9-13900K@5GHz, 64GB, RoG Strix B760F Gaming, Asus Tuf Gaming RTX 4070 OC Edition, 1+2 TB SSD's, 6+4TB HD
👿 Mac Mini M2, Sequoia 15.2, 16GB, 500GB SSD
👿 Nas 10TB
👿 Poser 13 and soon 14 ❤️

𝑀𝓎 𝒢𝒶𝓁𝓁𝑒𝓇𝓎