this is just an idea but how many pics are you aloud in the psp photo directory unlimited?
because what if we tried to have loads and loads of pics in the photo directory including tiff it may cause a crash from the psp trying to load all of the pics and since it dont have that much ram it may run out of memory and crash
because the psp loads them all so then you can browse all your pics without the pics having to loaded again
or maybe having a very large pic thats is like 20mb in size and has a large resolution the psp may not be able to load it and crash
p.s. this is just an idea and im not very experienced with the psp so dont flame me