import os
for root,dirs,files in os.walk(r"C:/"):
for file in files:
if os.path.basename(file)=="f.jpg":
print(os.path.join(root,file))

import os
for root,dirs,files in os.walk(r"C:/"):
for file in files:
if os.path.basename(file)=="f.jpg":
print(os.path.join(root,file))