When trying to open a file in an application you can use Quick Look in the open dialog. Just select a file and press the spacebar to bring up a preview of the image, media or document. You can leave the preview window up and use the arrow keys to navigate between files to find the one you want.
Related: Quick Look to iPhoto, Quick Look in Full Screen, Search To Open, Quick Look Full Screen, Quickly Always Open With.

Unfortunately this doesn’t work with aliases. While finder does correctly display the file that an alias points to in quick look, doing the same in an open file dialog just displays a generic icon and not the file that the alias actually points to. Could this be a bug?