edeainfj:
Why not just show the picture in its actual size on the puzzle page?
Without getting into too technical issues: The applet has a fixed size - width, height. In large multis, if we set the "so-called" actual size (do you know that there is no such thing as actual size?) the large multis would have taken a lot of space from the screen, caused the solver to scroll to the left/right and down/up, and not getting the whole preview. Moreover, in large multis the solvers look for the details and want to have the multi bigger, even bigger than the "actual size".
We do consider removing the lines that separate the parts. But it'll be done after fixing real bugs.