Problem: Use of large PictureFill symbols creates big SXD files
Use of large PictureFill symbols in ArcScene will result in large scene documents (*.sxd).
By design, PictureFill symbols are saved with the document; thus, if large images (example, used for globe image texture or detailed trees) are used for feature symbols, they will create large documents on disk.
Solution or Workaround
Avoid using large images as a source of PictureFill symbols. Most systems will resample large image textures to 1024x1024, so there's no point in using a source image larger than this. Resample source images ahead of time.