Normally jpeg are good enough. Jpeg is a file compression format. Infact it will compensate the image quality for compression.
Thus, it's still not the best format to save your digital work in. The best to use however is TIFF format. The is the highest quality you can save you work on. Quality of image is also dependant on how you resize your image, the scanning source, the settings you use to scan, the file format you choose to use in your digital camera, the resolution of your camera. All these will factor into the results of the digital image.
If you are sending it for printing, I will suggest you to have 2 versions of format. If permissable by the printer's equipment, the best choice would be to use TIFF format.