What is the problem with saving? You should scan in photoshop using the Import -> scanner as mentioned above... then, make all your adjustments, etc to the scan using layers. Save as a .tiff and import into fotofusion... if ff must take .jpgs, then either just save as .jpg and ignore the tiff or save both copies. You can save the tiff as many times as you'd like.. nothing wrong will happen.

And.. just as an fyi... you can use LZH compession on a tiff file and it wont' affect anything...