In the Forgery Detection lab, scan all five pictures carefully (the game requires you to scan them all). The one with drawings underneath is the real one.
Later in the game, you will use the same device on a painting sent to you, using the same technique.
Pass the x-ray wand over a painting, and you will see what is under the existing artwork. It may be another painting, or old sketches on the canvas. This is a clue that the painting is authentic, because famous painters hardly ever threw away expensive canvas when it could easily be re-used.
You use it.
Once you get the key from the curator, go back to Counterfeit island and use it at the Inspector's house.
In the Forgery Detection lab, scan all five pictures carefully (the game requires you to scan them all). The one with drawings underneath is the real one. Later in the game, you will use the same device on a painting sent to you, using the same technique.
You use the key from the Curator to unlock the Inspector's house in the CountrySide.
You don't ever even use the boat.
Go back to Counterfeit Island and use it to open the Inspector's house in the Country Side. On the way, the street artist gives you a clue as to what to look for in the house.
When you get past the Black Widow's guards, then you will use it to enter her layer. Have fun! :-)
a girl named paisley
The island was released for free general use on January 4, 2010.
The key to the investigator's chest on Counterfeit Island is hidden in the bushes to the right of the cottage. You need to use a stick to reach it and then unlock the investigator's chest to get the next clue.
Having checked, she is neither in the jail on Counterfeit Island nor in the County Prison on Super Power Island. There does not seem to be any other facility for her in Poptropica (unless they decide to use the dungeon on Astro Knights Island).
The same way you got in to get the picture piece : use your key.