Lab 5 Writeup

Be cynical—IT people don't believe everything they see because IT can help people lie.

In this lab exercise, we'll work with digital images using digital cameras and Adobe Fireworks. The pictures you take will serve as the basis for your work in project #5.

If you know how to use Photoshop or some other image manipulation program, you are free to use that instead of Adobe Fireworks. Unfortunately, we do not have Photoshop installed on our computers because it costs a good deal of money for the license; the ITC does have some computers with Photoshop installed. You may actually be able to find image-manipulation programs online, many of which work similarly to Fireworks and Photoshop (at least as far as this lab is concerned).

Modifying a Photo

  1. Take a digital photo. Obtain a digital photo of yourself. If you don't have one handy, you can ask someone to take your picture with a camera.
  2. Digitally modify your photo. Transfer your chosen picture to your F: drive. You can now digitally modify your file, as follows:

Here's an example image of Prof. Vander Linden that he modified.

Shrinking a Photo

When you build a webpage and would like some photos to decorate it (like Calvin's website and Vander Linden's personal homepage), you need to work to make the images as small as they can be.

Vander Linden chose to reduce his image's size down to 15–20 kilobytes. Photos taken by a digital camera are much larger than this. (An iPhone picture is around 70kb; an image from a real digital camera will be at least 800kb, even at modest resolutions. Scanners will also produce very large files.)

Modern suggestions for websites say that images should be 30–100kb in size, and the images on one webpage should add up to no more than 100kb. Wait five years, and these numbers will go up again.

Try shrinking down your image twice, into these two ranges: 15–20kb and 30–100kb. Here's how:

  1. Make two more copies. Take the modified copy of your image (the JPEG one) and make two more copies. You may want to use small and medium in the names of these copies so that you know which file is supposed to be small and which one medium sized.
  2. Shrink up the images. Open the images in Fireworks, and shrink each one in turn. Some things to try:
  3. Check your work.When you're done, you should check to see that the new image files are at the right sizes. From "My Computer", navigate the folder with your images. Use a details view of the files to see the file sizes.

Mess Around with Fireworks

If there is time, you can play around with some of the image manipulation features provided by Fireworks. This is to prepare you for Project 5! You could do any of the following:

Parts of Project 5 are "due" earlier than normal, so it's worthwhile getting started immediately! Again, you can do any of this work in Photoshop or another image manipulation program if you like.

A Challenge

If you have extra time and would like to get some extra credit for this lab, try to solve the following challenge. This one is more difficult than past challenges, but quite interesting.

This challenge is to create an image with a secret message embedded in it. This is known as steganography.

Use one of the following websites to embed a message in an image:

Use a picture and passphrase that you don't mind being public. Also, make sure you can decode the finished product to get your message back.

Submitting your Work

Submit the following files as attachments for Lab 5 in KnightVision:

In the "Comments" section of your Lab 5 submission on KnightVision: