In Minecraft, paintings are 2D textures applied to blocks. A mature texture pack specifically targets the (Bedrock) or individual painting files (Java) to swap original pixel art with higher-resolution adult images.
Replaces standard 1x1 and 2x2 paintings with high-resolution classical nudes from the Renaissance era. Minecraft Texture Pack With Nude Paintings
Most servers have strict rules against NSFW (Not Safe For Work) content. Even if you are the only one who can "see" the textures (since resource packs are client-side), sharing screenshots or streaming from a server with these packs active can get you banned. In Minecraft, paintings are 2D textures applied to blocks