Top's texture quality bad when paired with other CAS items?

Hello! I tried this and it actually worked! Maybe I messed something up with my shadow map, but now I know what area I need to fix, thanks so much!

So if you were to export the shadow map as png from any maxis outfit, you’d see that the white background exists only in places where the shadow exists, everything else is transparent. In your case, the whole background is flooded with white.
The shadow maps work like Multiply blending mode in photoshop, except for, I guess, not as good. In photoshop the white color simply disappears, in ts4 case, it worsens the quality of the diffuse textures it overlay. The more times this happens (more items put on a sim), the worse it gets.

So what you need to do is the same thing maxis does: add the white background only in places where the shadows exist, not everywhere.
Aannnd you must do this in .dds format instead of png because the way s4s convert .png to .dds creates black lines that are then noticeable in-game.

So do this:
- open your shadow map, using the marquee tool select the areas where the shadow are like in the pic;
- switch to channels and choose Save selection as channel;
- save as .dds, choosing bc3 (newer versions) or dxt5 (older), enable Generate mipmaps