If you plan to use images taken with a digital camera, or download or purchase them, you will need to adjust the images to suit your needs. The most common adjustments are to image size, brightness and contrast, and color balance. SnagIT can accomplish this task. It is not the most powerful tool, but it is adequate.
Image Size, Some General Considerations.
Many students' computers display 640 pixels (a pixel is a picture element) in width, and 480 pixels in height, especially monitors that are 14 or 15 inch monitors in size. Some newer computers display 800 x 600 pixels, or even 1024 x 768 pixels. It is always a good idea to assume that students will only be capable of displaying 640 x 480 pixels. So make your images much smaller than 640 x 480 so that they fit in one screen without scrolling.
Opening an Image File in SnagIT
Start SnagIT by double clicking the icon on the desktop.
From the Input menu, select Graphic File to open a file.
From the Output menu, select File to save the edited image as a graphic file.
Simultaneously press the "Hot keys" Control, Shift and p to bring up the Open file dialogue.
Change the file type to open to JPEG, .jpg.
Open the file galaxy.jpg on your diskette.
SnagIT displays some information about the file you opened in its status bar in the lower left hand corner. The first number, 478, is the width in pixels, and the second, 448, is the height in pixels. The third number is the number of colors in the image's palette, in this case 16M, or 16 million.
Cropping and Resizing Images, General Considerations
Two of the most frequently used techniques are resizing an image, to make it larger or smaller, and cropping an image to remove unwanted portions. Remember that the smaller the image, the faster it downloads. Removing unneeded parts will save download time.
In general, it is better to crop an image first, to remove wanted parts. Then, the image can be made larger or smaller to accommodate the needs of your web page.
Cropping Images Using SnagIT
Move your mouse pointer inside the image. Your pointer changes to cross hairs. Click once in the upper left hand corner to begin selecting part of the image. Drag your pointer to the right and down. Release the mouse button near the bottom corner.
A rectangular selection box is drawn on the screen.
From the Edit menu, select Crop. The part of the image inside the selection box remains. Outside the selection box is discarded. You can return it to its original content by clicking Edit, Restore.
Resizing Images Using SnagIT
From the Image menu, select Scale.
Choose Edit, 400% to make the image large. Note that at 400% the image looks good. Many images, especially those that are scanned have jagged edges when enlarged significantly.
Choose Edit, Undo to restore the original size.
Choose 75% to make the image smaller.
Choose Edit, Undo to restore the original size. Note that choosing Image, Any Scale allows you to have fine control over how the image is sized.