Attribute value not allowed on element input at this point.

When i check my website for w3C validation it shows two errors, but concerning to a file into my wordpress theme images file (images/ico-search.png).. The two showed errors are: Line 128, Column 158: Attribute value not allowed on element input at this point.and  Line 128, Column 158: Element input is missing required attribute alt.When i go to this file in my ftp database i just deleted this image because its for no use for my website. So it isnt there anymore. Nevertheless, the error is still showing. Why is that? And how can i solve these two errors when the file isnt there?Thanks a lot!Melissa