An illustration of a rectangular picture made from different colors. There is a small black hole in the middle of the picture which gives the impression you are looking inside a tunnel.
This is a completely free image Colorful Tunnel 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.