Use View in Browser to view any HTML message that does not display correctly in Outlook or when you want to print a message and have better options than Outlook’s print option offers. To view an HTML message in a web browser, you need to open the message! The View in Browser command is not available in the Reading Pane. You could save the message as HTML and open the HTML is a browser, but this is not necessary (and too much effort!) since as you can open messages in a browser directly from Outlook.
When you send an animated gif, you'll only see the first frame, but the recipient will see the animation if they use an email client that can display animation. If you don't need to see animated gif's, use form fields, or print a selection from the message, Outlook renders HTML formatting very well, but it may not always be 'perfect' and a browser will do a better job. Outlook's printing capability is also limited and you'll have more print options (such as print selected text) if you use View in Browser.
Outlook doesn't display animated gif's (only the first frame displays), form fields or any active content in email, all thanks to numerous viruses that spread like wildfire through Outlook, so the powers that be locked Outlook down: no active content will display in email.
