If you have the model already, just right click and save as and name and place the map .jpg with the model. Then while in Bryce use the material editor and change the image texture from the default one... Or did you mean to ask how it was made to begin with? In that case, it was UV mapped in Wings and the resulting template was painted over using JASC Paint Shop Pro (any 2D program would work.). The image is then brought back into Wings to check how it wraps on the models, and then is adjusted again in PSP. (Repeat last two steps until it's right.) To me, this is a lot more work than making the model itself.

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Barbequed Pixels?

Your friendly neighborhood Wings3D nut.
Also feel free to browse my freebies at ShareCG.
There might be something worth downloading.