Either part1 or part2 is a cell array of strings and needs to be a string instead. You could look back further in your code and make it a string instead of a cell array of strings, or you could use
name = strcat( char(part1), '-', char(part2), '.jpg');
I would normally code the char(part1) as part1{1} but I do not know which of the two is the cell and using char() covers all the cases.
