Option 1: Expand Individual Images to full size
Hold the mouse pointer over the image until the icon below appears in the lower right corner of the image and click it to expand to full size.
By default, Internet Explorer resizes the image to fit entirely in the browser window.
Option 2. Turn off Automatic Image Resizing.
In Internet Explorer's toolbar navigate to Tools > Internet Options > Advanced
Scroll down to the Multimedia section
Uncheck Enable Automatic Image Resizing