From the menu bar, select Edit.
From the Edit menu, select Preferences.
From the Category list on the left hand side, click on Advanced.
From the list of Advanced options on the right side of the screen, uncheck the box for "Automatically Load Images"
Click on the plus sign next to "Advanced" from the category list on the left side of the screen to display the Advanced options.
Click on the entry for Cache.
Click on the button for Clear Memory Cache; click on OK when prompted.
Click on the button for Clear Disk Cache; click on OK when prompted.
Click on the OK button at the bottom of the screen. An "Images" icon should appear on the tool bar at the top of the browser (if tool bar is displayed).
Display the page you're checking. You should see the ALT text you've supplied for each image
Repeat steps 1-3 above, and reverse step 4 above to restore automatic image display.
From the menu bar, select Tools.
From the Tools menu, select Internet Options.
From the Internet Options box, select the tab for Advanced.
From the Advanced Options list*, scroll down to the Multimedia section.
Uncheck the box next to the Show pictures selection.
Click on the OK button at the bottom of the dialog box.
Display the page you're checking. You should see the ALT text you've supplied for each image
Repeat steps 1-4 above, and reverse step 5 above to restore automatic image display.
* Note the "Accessibility" option group at the top of the screen. The Always expand ALT text for images option is what determines whether or not ALT text tool tips will be displayed.