Marshall Adult Education



TECH TIPS:  Working with Pictures

In this Tech Tip, you will learn about:

  • Graphic File Formats
  • File sizes
  • How to resize Pictures.

Graphic File Formats

There are many different types (formats) of graphics. If you want to learn about the different types (formats) of graphics, visit this site:

We will be concerned primarily with the formats that are used on the internet. There are 3: Gif, JPEG, and PNG. A brief explanation of each.

  • Gif - this format is used primarily for line-art, such as cartoons, drawings, - just about any graphic that is not a photograph. Gifs can also be animated (known as animated gifs). Gifs can show only 256 colors – not real suitable for photos.
  • JPEG - this format is used primarily for photos since it can show millions of colors.
  • PNG - this is a relatively new file format used on the internet – it comes in 2 "flavors" - PNG-8 which displays 256 colors and PNG-24 which can display millions of colors. It is not used a lot on the web, giving way to the better know gif and jpeg formats.
File Sizes

First, a word about bytes and kilobytes (KB) and megabytes (MB) and gigabytes (GB). (This is making me hungry – oh – wrong kind of bites!)

  • 1 byte is one character (letter or number) pressed on the keyboard.
  • 1KB is 1000 bytes.
  • 1000 KB is one megabyte (MB) (or one million bytes).
  • 1000 MB is one gigabyte (or one billion bytes).
  • OK – lets quit with gigabytes – although terabytes are just around the corner.

To put things in perspective:

    ...a 3½ floppy disk can hold 1400K or 1.4 MB.
    ...a CD ROM can hold 700 MB.
    ...a DVD can hold 4.7 GB.
    ...and most computers sold these days come with 40 to 80 GB hard drives.

Gifs take up the least amount of space on your hard drive. A small gif may take only 3K (or 3000 bytes). A large gif would be 20K or more.

JPEGS (remember, these are mostly photographs) vary greatly, depending on the resolution of the picture (the number of pixels). You can set the resolution you want for most digital cameras. Depending on the capabilities of your camera…

...if you set the resolution to "standard," your picture might be 640 x 480 pixels and would be around 70K.
...if you set the resolution to "High," your picture might be 1024 x 768 pixels and would be around 269K.
...if you set the resolution to "Super High," your picture might be 1600 x 1200 pixels and would be around 814K.
(This is just an example – a higher megapixel camera would go much high the 1600 x 1200).

If you are going to email pictures, you should try to reduce the size of your pictures. A 640 x 480 picture is a good size to use for emailing pictures. They will fit nicely into the window of the email and the file size will download quickly.

Resizing Pictures

You can resize a jpeg or a gif very easily with a FREE program called PIXresizer. You can also resize an entire folder of pictures at the same time. Other neat things you can do with this software is

  • Rotate the picture
  • Change the file format of the picture
  • Change a picture to grayscale
  • Print the picture

You can download PIXresizer here:

If you use Windows XP, you can also download the FREE Microsoft PowerToy, Image Resizer. This neat little utility will resize a picture and rotate a picture with the click of a button (just right-click on the picture). You can download Image Resizer here: