Making quick-and-dirty bump and normal maps is not that hard to do in the GIMP either, but Materialize does a much better job of it, so I don’t bother anymore. If you have only a colour photo, but you want to drive the colour yourself in Blender, you could convert it to grayscale in the GIMP before taking it into Materialize, though you could also do that in Blender itself afterwards. I generally first prepare my images in the GIMP, remove things I don’t want, clean the edges (especially if the original is a jpg), change scale, hue, saturation if needed, align the object, and isolate it on a transparent background, so any grayscale conversion is just part of the workflow.
If this is not a close-up object in your scene but still clearly visible so you need the edge detail, but you want to keep it low-poly, you can subdivide it high so it displaces well, and then bake a new normal map to use on a low poly copy without displacement. It’s pretty amazing what just a good, detailed normal map can do.