What types and sizes of images can I use on my portfolio page?

First, you do need to have any images you want to use in digital format (that means as a file on your computer). These images must be saved either as ".jpg" files or ".gif" files (if photos, usually you'll want to show them as ".jpg" files). In order to display properly, your images should be saved as 72 or 96 pixels per inch (this is called the resolution of the image) and should be at least 800 pixels wide (the vertical dimension can be whatever it needs to be to look proportionate). If you have images that don't conform to these specs, most image editors (like Adobe Photoshop, Corel Paint Shop Pro, Photoimpact, GIMP or similar) will be able to re-size the images (this is also known as "re-sampling" the image). The online help files of your image editing program should be able to give you more information on each of these aspects of manipulating your images.