For textures I would have thought you would want to use .png or .tif - something less messy - but hey, I'm no expert, maybe jpeg 10 or 12 is just as good ?

Then again I don't like to lose any quality anywhere, now that drive space is cheap and computers are fast. The only reason I would use jpeg would be for a web image on a site or page where you MUST limit your file size. Last time I checked JPEG was "lossy" - that means if you keep opening and saving a jpeg, it degrades, to simplify.