Q: Images auto fill container div no matter the number of images I want to create a container div and add "X" amount of images to it. But no matter the number of images inside, they will always fill the entire container evenly.
Heres an image for better understanding:

HTML/CSS only would be best, but of course I would be open to other ideas. Sort of new at this so any help would be great.

A: You can do this with CSS. The trick is to make the images float:left; with a width:50%;. If the last image happens to be an odd-numbered image then we need to make it full width. This is done using the selector img:last-child:nth-child(odd). 
Here's the full CSS for the images:
CSS
img {
    float:left;
    width:50%;
}

/*
* This makes the last image (if odd)
* full width.
*/
img:last-child:nth-child(odd) {
    width:100%;
}

/*
 Special rules for 2 images
*/

div.container > img:first-child:nth-last-child(2) {
    width:100%;
}

div.container > img:last-child:nth-child(2) {
    width:100%;
}

And here's the full demo.
