There is no such thing as a “Studio ID” of a decal – to show the decal in both studio and in-game, you’ll be using the same ID from the website. I would assume this misconception came from the difference between decals and images: when you upload a decal, it’ll also upload the same thing but it will be an image with a different ID. If you try inserting a decal ID into a GuiObject like a ImageLabel or ImageButton, studio will find the correct ID for the corresponding image and replace the ImageLabel’s / ImageButton’s image to the ID of the image
The problem is because your script likely failed to work as intended, or the decal failed to be loaded because it was either denied, it didn’t get the correct ID, or its still awaiting approval from the moderators (the latest should not likely be the case because it has been a while since your last topic was created)
Have you tried checking the output to see if the image failed to load and has the correct id that was inputted? What type of script is it? Where is it parented?