change resolution to 300 dpi using bridge?

[bnilsen]

I'd like to change a folder of images that I'm viewing in Bridge so that they display at 300 dpi. I've done it before (I think!) and I can't remember how or find the action or script I wrote to do it. I took them with a 12 megapixel camera but when I downloaded them from the camera, they all show up as 72 dpi when I open them in Photoshop CS5.

They need to be uploaded to a yearbook website which requires the images be 300 dpi. I'd rather not change them individually.

Any help??!

Thanks.