The problem with dates

So it seems dates are a hellish nightmare with php… well for what I am trying to do. I have tried about 6 or 7 different ways to achieve what I want but each have their own issues grrrrr!!!!

What I want to do is tag each image with the date it was for e.g. 1/1/14 so that shows up in the lightbox description. Easily enough eh but at the same time I need to work in part of php into my loop to know when it comes to the end of a month, so it can then close that set of images, then place the heading for the next month and start for the next set of images.

Sounds easy doesn`t it and prob is but for some reason everything is going a bit tit’s up. I can get part of it working each time via each method but not all of it.