Error using imwrite (line 528) Unable to open file

Hello,

I used

 imwrite(P, fullName,'.jpg');   %fulName is a path of .jpg file

and getting following error

Error using imwrite (line 528) Unable to open file

[Walter Roberson]

The value stored in fullName designates a file in a directory that does not exist or which you do not have permission to create files in, or designates a file that already exists but you do not have permission to write to.