okay so the old one is
http://emeraldforestseattle.com/attachments/79039-th_9.jpgand the new one is
http://emeraldforestseattle.nuclearfallout.net/attachments/79039-th_9.jpgso you would have to put this
UPDATE w3t_Users
SET U_Picture = REPLACE(U_Picture, 'emeraldforestseattle.com','emeraldforestseattle.nuclearfallout.net');
need to know exactly what the old path says and what the new path says