I have a scenario where I want to check whether the alt-text of image, added on mail, is shown correctly while sending a mail or not. To test this, we added an img tag in mail but gave nothing in src and added an alt-text. Now the problem is that the outlook-2010, instead of showing the alt-text, shows its own message "the linked image cannot be displayed.....". How can we avert this message to check our alt-text. Is there a better way to test such scenario in outlook-2010.
You can't control such things. You have control over an alt text styling (in some cases), but some mail clients will do whatever they want with your html and inline styles.
The only solution is to make sure your mail can be read without images, like adding a text close to the image. Most of the time, my templates have both the image and the text close to one another.