There are several ways to open an image with Photoshop. One easy way is to grab the image file, drag it into Photoshop, and drop it into your workspace. This way you can skip the whole dialog box or the right click menu from within the OS. I know this works with Windows, but I'm unsure about this functionality with Mac users. The one hook to using this method is that you need to have Photoshop already up and running.
Another perk of this method is that you can place a new image into another image as a new layer. You just need to have one image already open in Photoshop, and you then drop it on the image rather than the Photoshop background. This is handy if you're working on textured photos, composites, or graphics.
In addition to that, you can grab images from your web browser by clicking, dragging, and releasing into Photoshop. Then you don't have to save the file to your computer before opening it.