I'll start form the bottom and work my way up explaining the uses of all the Photoshop tools that I use.
Image Ready - button lets you edit the image in Adobe Image-ready.
Screen Modes - Standard lets you see all the images you're editing in separate windows, the next button maximizes all the windows of the images to the workspace, and the full screen mode maximizes the image to the whole screed over the task-bar.
Foreground and Background Colors - lets you see and change the colors you're editing an image with.
Hand Tool - if you know what it does, tell me.
Zoom Tool - Zoom in a particular part of the image.
Eyedropper - Using Alt you can copy a certain color form an image and draw with that color on the image or a separate image.
Objects Tools - There are Rectangle, Rounded Rectangle, Ellipse, Line, Polygon, and Custom Shape Tools, each of which can be draw on an image.
Text Tools - Let's you put text on an image.
Smudge Tool - Smears the image in the direction you choose.
Blur Tool - Blurs an image in areas you select.
Paint Bucket Tool - Fills a chosen color on to an image with the selected color.
Erase Tool - Erases an image to its background, either white, a selected color, or transparent.
Clone Stamp Tool - Using Alt you can select a part of an image and recopy that part to a different image or to a different area of the same image.
Brush Tool - Draws lines of a selected brush in a direction you choose.
Pencil Tool - Draws lines of a selected brush in a direction you choose, without anti-aliasing.
Crop Tool - Crops the image to the area selected.
Move Tool - Moves the objects or layers in the image, or the image itself.
Wand Tool - Selects a color and its shades so that only that part of an image can be modified or added effects to.
Lasso Tool - Lets you select a part of an image to be modified by itself.
Marquee Tools - Let's you select a defined object of an image or creat a defined object.
Photoshop Tools lets you create your own workspace that fits you the best.
You can move or get rid of any options and settings windows in your workspace so that it can be used to your best interest.
