Is there a way to easily resize an image as a Ninepatch would resize in photoshop?
A ninepatch, for those unfamiliar, is described here. In a nutshell, you can take an image and put a few pixels on the outermost pixels to represent which areas should stretch and not stretch when they're used on UI widgets of varying sizes. That's great if the program you're working with knows how to understand a ninepatch style image.
Is there a way to resize something in photoshop in the same way? Normally I would just scale it, but that doesn't work if I want to keep the borders edges a specific thickness and only stretch the center portions.
If you stick with vector shapes in Photoshop, that will give you want you want.
If you need to stretch raster images, I believe Adobe Fireworks now offers that feature.
If these are gui elements for web, note that you can do a lot with CSS now and may not need actual images.