In the rest of this tip we’ll walk you through adding Bookmarklets in Safari.
To add these Resize Bookmarklets to Safari, just drag the links from this webpage up into your Bookmark Bar.
Once they’ve been added, click on the bookmarks button to organize your Bookmark Bar. Add a folder to hold all your resize scripts (Bookmarks > Add Bookmark Folder) and group them under a single pull-down menu.
Source: This tip comes from CreativeTechs’ own Kyle Pauley. For some addition resizing finesse check out this post on 5thirtyone.com.