If you use OS X 10.4’s Preview to look at or manipulate images, one thing that may bother you is the apparent lack of a scrolling tool. In most graphics programs, the scrolling tool is represented by an icon of a hand, so you may also hear this referred to as the hand tool. With the hand tool, you can move about in an image which is larger than that which fits on the screen. For instance, you might be working with a 2,500-by-1,200 pixel image on a screen with a work area substantially smaller than that. So if you’re viewing the image at full size, you’ll have both horizontal and vertical scroll bars. Sure, you could use the scroll bars to move about, but the problem is that they only move in one direction—so to move diagonally, you need to drag one bar, then the other, etc., until you get to where you want to go.
The hand tool, though, simply lets you click and drag to move the image around within the visible work area. This makes is simple to go just where you need to, without having to flip between two different scroll bars. Sounds useful, and indeed, if you open a PDF in Preview, you’ll see that you have scroll tool available—just press Command-1 (Tools -> Scroll Tool), or choose the first icon on the Tool Mode section of the toolbar. (Note that the scrolling tool will only work if you are viewing the image at actual size, and that size is larger than the window size.)
But open an image in Preview, where such a tool would be really useful, and it’s nowhere to be seen. Command-1 does nothing, and if you look, the Scroll Tool menu item is grayed out. There’s also no Tool Mode section on the menu bar, nor can you add one via the Customize Toolbar menu item. However, if you press and hold the space bar with an image open, you’ll see the cursor change to a hand. There is it, the hidden scrolling tool!
Now, it’s a bit of a pain to hold down the space bar while dragging. But you don’t have to—once you start dragging, you can release the space bar. The cursor will switch back to that of the select tool, but you can continue dragging. If you need to reposition the mouse, though, you’ll have to press the space bar again to re-enter the scrolling mode.
While it would make much more sense for Apple to simply enable the Scroll Tool menu item with images open, at least there is a workaround. (And this shouldn’t be an issue in pre-10.4 versions of Preview, as I don’t believe they had this split personality for tools available in PDFs and images—I might be wrong about that, though.)