Batch process: how to scale images without enlarging small ones?

Hello,

I am a beginner on Photoshop.

I need to resize several thousand images contained in a directory. These images are of all sizes, from 150x150px to 6000x4000px
To lighten them for publication on a website, I don't want these images to exceed 1500px wide.

Fireworks allowed me to do a batch process that only resized images larger than the desired size.

How can I do the same thing with Photoshop?

In Photoshop, the script for resizing images via File > Scripts > Image Processor transforms all images to the specified size, even the smallest.

You would probably have to build an action for this, but I have no idea how to do it... It's a pity that this function, which seems basic to me, doesn't exist on Photoshop.

The Adobe support didn't know how to answer this question...

Thank you in advance for your help,

Phil