I've been doing a lot of web searching to get an answer to my problem.

How do I improve resolution, say from the standard 72ppi to a printable 250ppi?

I've read and reread this tutorial:

Image Resolution Pixel Dimensions Document Size Adobe Photoshop Tutorial - Page 2

It seems to say that if I have a 10" X 10" file open in PS and the ppi is 72, by changing the dimensions to say, 5" X 5", the file will compress ending up with a higher resolution. When I do this the ppi stays at 72 and the picture file size reduces accordingly.

What am I missing?

Thanks,

Neil