Best format for textures in image processing

I have not used On 1 myself other than a quick trial but the Raw file is not a bit mapped file which you will need for a texture. The reason why you see it in the Browse module is almost certainly because it is displaying the embedded JPEG thumbnail. You should save a copy of the texture file as a JPEG. There are videos on the ON1 site detailing all of this and all the examples are JPEG but TIFF may be possible.
Dave
Dave