I have following:

image1.jpg under /images
image1_md.jpg under /images/medium
image1_lg.jpg under /images/large

in admin:

suffix for medium images is _md and for large images it's _lg

image sizes are as follows:

default 85x85
medium 150x150
large 250x250

I've fixed the sizes under admin.
Here is my question:

main page only shows new products for month %s (what's new)

All I want is to show images from "/images/medium" folder instead of default "/images". folder (for what's new listing). I don't want to simply move medium images to images folder and rename them because I want to keep the small images too, so I can use them on other product listings and so on.

As far as i see, what's new page calls out "tpl_modules_whats_new.php" which calls out "tpl_columnar_display.php". I don't see "columnar_display" changes anything rather than being a function to count and display images.

Which php page I need to change so I can have what's new listing look at to /images/medium folder.

Hope I was clear.
Thanks in advance