PHP Code:
$chars=explode("," , "a,b,c,d,e,f,g,h,i,j,k,l,
m,n,o,p,q,r,s,t,u,v,w,x,y,z,
A,B,C,D,E,F,G,H,I,J,K,L,M,
N,O,P,Q,R,S,T,U,V,W,X,Y,Z,
1,2,3,4,5,6,7,8,9,0,_");
$name = '';
for($i = 0; $i < $namelength; $i++) {
$name .= $chars[rand(0,63)];
}
$name .= '.jpg';
You could also randomize the length of the names.