Putting in custom grid lines in figures

Hi, I'm trying to make figures of heat senses and I need custom grids.

So I have a 150*150 matrix that im converting to a figure, but I want to label the source of the heat with two crossing lines.

So on my figure, i want to show these lines : x = 25, x = 125, y = 25, y = 125 so that at the crossing points such as (25,25) lies my heat sources.

All I need to know is how to input these lines into the figures. It would be amazing if they could be dotted lines too.

Thank you for the help!

Answer 1

[David Barry]

https://uk.mathworks.com/help/matlab/ref/line.html