There are several tools available on the Adobe Reader toolbar for resizing an image.
Zoom in Tool
This tool looks like a magnifying glass, and can be used to zoom in on a specific area of the page or article. Select the tool, then click the area of the image you want to make larger. Keep clicking until the image is the size you want.
You can also select this tool, then click and drag to select a specific portion of the article. Acrobat Reader will enlarge the selected area to fill the screen.
Zoom In and Out buttons
The Zoom In button is a + sign, the Zoom Out button is a - sign. Use this tool to make the entire image larger or smaller.
Resize drop down menu
This drop down box between the Zoom In and Out buttons lets you select a specific percentage size to display the image.
Click this button to print out an article image or a page image.