Yes, once you have the jpeg made into a mat, applied to your object, and the object selected, open the material editor, up where it says edit. You'll note that the preview window shows your material. Choose what section you want your material to go in, then click on add. Just give it a name and whatever comments you want and click on the checkmark. That adds it. You can also export it as a .mat file. But beware, some jpegs or bmps make huge mat files. I have one of cat hair that's so large I can't even use it because it's so slow

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