In case someone has the same issue. the problem was with ie not sending the file in the input having the id of content and style display:none :
<input id="content" name="content" type="file"
style="display: none;"
accept="image/x-png, image/gif, image/jpeg" />
I figured out the problem using a software to debug the http requests sent from the browser.
I solved the problem with using a simple input of type file.