I'm playing on the Mac, so forgive me (and correct me!) if I don't get the Windows details quite right!
I'll explain this for the benefit of people new to FM, so most of you will know how the pictures folders were organised in previous versions, but I'll go into it anyway.
1 Go to:
(Windows)
My Documents/ Sports Interactive/ Football Manager 2008
(Mac)
~/ Documents/ Sports Interactive/ Football Manager 2008 (where '~' is your home folder)
2 In 'Football Manager 2008', create a folder called 'Graphics'
3 In this, create a folder called 'Pictures'
4 In this, create folders called "Kits', 'Logos' & 'Players' and in these you may like to create subsequent folders for different countries, continents etc, just to keep them organised.
5 Place the graphics in the relevant folders.
6 Launch FM. On preference screen, untick the 'skin cache' box & tick 'always reload'.
The pics should now load OK.
Hope this helps!