Adobe Photoshop is an image editing, or image creating application, with alot of advanced and useful tools.
Definitions, understanding terms:
Image - picture, a visual representation of an object or scene or person or abstraction produced on a surface.
Pixel - the information stored for a single grid point in the image. The complete image is a rectangular array of pixels. A pixel consists of a single color.
Diffrence between canvas size and image size.
The image is an object that was drawn and when changing the size of it, it either shrinks or expands, cavans is the space provided to draw the image on, decreasing the size of the canvas doesn't shrink the image but cuts it off, when increasing the cavas size there is more space provided and you can draw out side of the image.
Transparent - if an image is not transparent, the image is automaticaly a rectangular size, if the image is transparent, for instace a circle will always be a circle, the canvas is transparent so the pixels around the circle are non existent.
Anti-aliasing - Smoothing or blending the transition of pixels in an image. Anti-aliasing the edges on a graphic image makes the edges appear smooth, not jagged.
Layer - layers pile on top of eachother, think of it as earth's layers of soil, crust and so on. You can change th order of layers, depending if you want an image under an image or the other way around.
Filter - under Filter you will find numerous effects you can apply to a image or selected region of an image.
Bitmap - A representation, consisting of rows and columns of dots, of a graphics image in computer memory. The value of each dot (whether it is filled in or not) is stored in one or more bits of data.
Grayscale - An image representation in which each pixel is represented by a single sample value representing overall luminance (on a scale from black to white).
RGB Color - The red, green, and blue (RGB) color system can represent a large portion of the color spectrum by mixing these three primary colors.
Lab Color - a color model developed by the Centre Internationale d?Eclairage (CIE). These standards are internationally accepted standards for all colormetric measurements. The Lab model, like other CIE color models, defines color values mathematically, in a device independent manner. Lab color is consistent color regardless of the device producing the color.
I'll start form the bottom and work my way up explaining all the tools that I use.
ImageReady button lets you edit the image in Adobe ImageReady.
Screen Modes - Standart lets you see all the images you're editting in separete 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 scread over the taskbar.
Foreground and Background Colors - lets you see and change the colors you're editting an image with.
Hand Tool - ...if you know what it does, tell me.
Zoom Tool - Zoom in a particular part of the image.
EyeDroper - Using Alt you can copy a sertain color form an image and draw with that color on the image or a separete image.
Objects Tools - There are Rectagle, Rounded Rectagle, Ellips, 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 teh 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 trasnparent.
Clone Stamp Tool - Using Alt you can select a part of an image and recopy that part to a diffrent image or to a diffrent 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 ati-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 remoddified or added effects to.
Lasso Tool - Lets you select a part of an image to be moddified by itself.
Marquee Tools - Let's you select a defined object of an image or creat a defined object.
Options and Settings:
Photoshop 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.
When creating a new file(File/New...) and you want it to be transparent make sure you choose Transparent under Contents.
At the end when creating transparent images you should always save them as PNGs, when selecting File/Save As...and click on the drop down arrow and select PNG.
If you weren't done with your work, and have created different layers, you can save it as PSD, so that you can finish later. Photoshop will save all your layers, unfotunately it doesn't save your history.
In the top menus you can edit Layers, Edit images(rotate, colors ect.), you can slect and customize your workspace, and in the Filter menu as I've said you can set lots and lots of effects to images. And under Help you will find tutorials on how to use photoshop.
-hope it helps
credits goes to cm+vixen