is the hook on a separate layer or is it just a random picture you want to tweak?
Either way you need to get the hook by itself on its own layer (either by pen tool or something else), then use the magic wand tool to select the empty space on the hook layer... Then ctrl+shift+i to invert the selection so it is perfectly around the hook. From there it's a simple matter of applying a stroke and outter glow on another layer (and it will look like its around the hook)... Then open the animation window and create 1 frame, on that frame... make sure the hook doesn't have the layer turned on that makes it "glow"... Create another animation frame and turn the "glow" on then one more to turn it off again... and then apply a tween to the two first frames... Depending on how fast or slow you want it to glow/pulse you add more or less frames in the tweening option. then tween the last two as well... This will provide a looping effect for the animation...
It'll start out as you see it now, then glow, then not, and then loop infinitely.
It sounds hard, it's really about a 5-10minute job.