What are the advantage and disadvantage of using both?
CSS
<input type="submit" class="removeBtn" /> .removeBtn{ background: url(Images/Remove.png); height: 25px; width: 25px; }Inline
<input type="image" src="Content/Images/Remove.png" />
Semantically speaking, you should always use a submit button. A user with a screenreader will have no idea what the function of your image input is.
Edit: as per comments, the image button will automatically submit a form as well as an input with type="submit"
<input type="image"> functions as a submit button too. But good point about accessibility, unless the image input's alt attribute mentions its submit functionality.input type="image". If you put this info into your answer, I will be ready to upvote.
<button><!-- MORE HTML!--></button>?<button type="submit">.