picture thumbnail size in apps

[ar723]

I have been trying to figure out a way to make my thumbnail size bigger when I am opening up pictures in apps. I have adjusted the size of my thumbnails when I am in Finder, but when I am in apps like photoshop, flickr, even mail, the thumbnails are still very small. Same thing when uploading pics to facebook. They are so small I am having a hard time telling who is even in the picture. So far I haven't had any luck figuring out how to change it or if I even can. Thanks!