   Can i get the size of video memory taken by a given d3dtexture object?
  since d3d compresses textures when loading them into video memory and also might generate mipmaps levels of themhow would i know the size of memory occupied by this resource.   
  Generally speaking, you can't (As far as I know). You could use IDirect3DDevice9::GetAvailiableTextureMem() before and after loading the texture, but that won't be particularly accurate.   