The solution to this puzzle is this


This solution is also mentioned in many other guides, but the reason is difficult to understand

That's why i decided to write this guide

It's easy to recognize that the icons below the paintings represent the missions


and each painting is hidden somewhere within the mission area

In the first mission Bad Call, the painting can be found by taking the elevator down and entering Rob's hidden room. You just have to open the door to see it

In Tiral by blood, the painting is located insider the locker W018
To open it, you'll need the key to VIP room. To access the VIP room, you need a VIP keycard, which is stored in locker M034. The key to M034 is inside locker W024, and the keycard for W024 is located in the solarium.

In Toxic love, the painting is found inside a drawer in the laundry room on the ground floor.
The laundry room is locked at first, but you can unlock it from the room with the man's body.

In Short cirtuit, you can find it by opening the cabinet in the storage room on first floor. It's initially hidden behind a mannequin's torso.

Near the grandma's apartment, there's a storage room.
Open the cabinet right next to the desk with the gardener's recording, and you'll find the painting inside.

You should first find the laundry room key on the first floor, and then open the laundry room on ground floor. The painting is inside a blue basket.

You can find it very quickly
just open the hidden door on the left wall.

The painting is inside the cabinet under the sink in the party house

Go to the area with multiple doors In the central exhibition
Open the white door that lifts upward between the restrooms. the painting is there.

It's in the control room on the hall first floor. You should use the step ladder to climb up onto the top of the cabinet. And walk across the pipes to enter the locked room. Open the safe inside to find the final painting.

To be honest, this puzzle is bad.
It's not intuitive at all, and there's no way to figure it out just by exploring the map.
It would've been better if the puzzle were more thematically tied to the Italian Job, or the animatronics.