I'll use the fractal below. It's shown here on a black background so it can be seen easily, but the actual fractal was brought into the photo file as a transparent png (no black). This fractal is suitable because (a) it is soft and lacking in hard edged definition (b) it has a nice warm color.
The image I will use is a straightforward church interior with lots of wood that will go nicely with the warm tones of the fractal image.
The settings used for the texture layer were mode=overlay and opacity about 50%, settings which produced this final picture:
Apologies that the last picture is smaller (Blogger changes it to the original if I try to make it any larger!) What I like about this approach is that it replaces a warming filter, the different shades in the fractal give very subtle changes in luminosity that make the picture more three dimensional, and while its effects are quite visible the fractal its self isn't.
The fractal was generated in Apothysis 7x (a freeware program) and picked out of a randomly generated batch (i.e. no skill whatsoever required :-)