You need mass and porous fabric to absorb sound via panels. Bass traps are going to be the best bet in a small room.

Paintings won’t do hardly anything to absorb sound because the material isn’t porous enough, nor is there Rockwool/fiberglass behind it to absorb.

I ran across a company that wraps their acoustic panels in decorative fabrics:

BUBOS Decorative Acoustic Panels,12"X12"X0.4" Sound Proof Padding Beveled Edge Acoustic Absorption Panel for Echo Bass Insulation,Ideal for Home & Studio Acoustic Treatment,6 Pcs,Infinite Loop https://www.amazon.com/dp/B083FHMWXQ/ref=cm_sw_r_cp_api_glt_fabc_NEMK2J3XN3KH4KXR2SB0