SetDirectory["/home/student/courses/MATH590/SETdata/BloodCells/JPEGImages"]

f=FileNames[];

n=Length[f]

Manipulate[Import[f[[k]]],{k,1,n,1}]

im=Import[f[[9]]]

d=ImageData[im];

Manipulate[GradientFilter[FillingTransform[MaxDetect[im,t]],1],{t,0,1}]