image resizing for print

We are an e-commerce company and wish to do a show case of our web sites in a presentation.I have been asked to make some posters and have done some screen shots. The current dpi is 72dpi, and the printers need the highest resolution possible. How can I resize to get the highest resolution possible. I tried resizing using "Image size..." to 300 dpi, then resizing back to the original 72(to see what it would look like), but when going back to 72 dpi it blurs the screen shots. what must I do?

Any help will be appreciated.

Thanks

yeah, not gonna work, sorry the images for your site were built at 72dpi, trying to size them up is trying to introduce detail that wasn't already there. bitmapped images exist as a certain arrangement of pixels, making them bigger just makes the pixels bigger.

if you're doing posters you can probably get away with 150dpi, 300dpi isn't really needed for something that big (some will try to tell you differently, but if you're not right next to it staring at it you won't notice). your best bet is to go to resize image and uncheck "resample image", then set your resolution to something slightly higher like 100dpi, you probably won't be able to go over 120dpi or so without starting to really lose some clarity.

there's also the option of rebuilding a comp of the site in photoshop or illustrator at a higher resolution so you can use that for print, or rebuilding pieces of the site (certain graphics, menu, etc.) and using those in a more abstract fashion. you may just need to accept you're not going to have an image of the site at huge size on your poster and simple use it as one of the design element. hope that helps...

chris