I'm making ad's in my game and I know how to sell stuff in game but I'm having trouble getting the image. If I had to get every Image and download and make a decal it would be pretty boring and it would take long. Is there a way just by taking the Product Id or something to get the image?
Yes, it is.
Simply use the following in the image
https://www.roblox.com/asset-thumbnail/image?assetId=0&width=420&height=420&format=png
After that, replace the 0 within assetId=0
with the id of the shirt/pants.
The ID of the shirt/pants will be the numbers found within the URL of the link.
Hope I helped.