Made some tests with rastering techniques. This one has been rastered in GIMP and then imported to Inkscape where I did Path-Trace. So it is a true vector image although it looks like raster.
This is a completely free image Gandhi (raster effect) that you can download, post, and use for any purpose.
Image License: CC0 No Rights Reserved
You can copy, modify, distribute and perform the work, even for commercial purposes, all without asking permission, and at no cost. This image is completely free.