How to jump to a particular place in the for loop if the if condition is satisfied?

I have some image files. I'm trying to perform some calculations using each file and if a certain condition is met, I'd like to go back to a particular line in the code and run it from there again. But, MATLAB doesn't seem to have a goto function and also, using goto implies bad programming so I thought I'd just iterate the for loop twice for a particular 'i' value which satisfies the if condition.

file = dir('*.jpg');
n = length(file);
for i = 1:n
    *perform some operations on the 'i'th file*
    if 'condition'
        *run the for loop again for the 'i'th file instead of going to the 'i+1'th file*
         i=i-1;
    else
        *go to next iteration*
    end
end

I have tried to code this by changing the loop variable 'i' inside the loop to 'i-1' so that on the next iteration, the 'i'th loop will be repeated again but doing so is giving the wrong output, though I don't know if there is some other error in my code or if the changing of the loop variable internally is the cause of the problem. Any help on this is appreciated.