Urgent help needed for custom objects i am making

[Creator´s Master]

Hi people, i am making custom objects in "The Sims 4 Studio" using Blender and Photoshop. not recolouring, doing new meshes from a vanilla one.

I am making custom painting for a collection but i have a big final problem and i canT find a solution in google for it, 6 hour trying it i am so fcking nervous haahah.

 

the problem shows when i put the custom painting in the game, exactly in the wall. i will put this pictures explaining the process.

 

please, someone has to know what happend in it.

 

Here in blender (looks ok)

 

Here in the sims 4 studio (looks ok)

Here in game HERE IS THE PROBLEM VISIBLE, IF YOU ZOOM OUT IT GET WORST GOING WHITE.

What i am missing? its maybe something about textures in blender? i change the LODs in TS4S, something about Alpha? Specular? 

Please help me with this so i can make my paintings collection to share here

The size of images is cos photoshop no problem with that

Thanks a lot