How to script file upload button

<input type="file" name="file" multiple="">

Hi guys, our company's website has this button for uploading multiple images. How can I create a script that automatically selects the images then uploads them? I already know the path of each images. I just don't want to script a click on the file upload button since I get a headache trying to make that work. My current goal is to script it with something like:

$files1 = "C:\TeamBuilding\Team Games.jpg"

$files2 = "C:\TeamBuilding\Team Prayer.jpg"

$oIE.getelementbyid("file").upload $files1, $files2

Then after the image upload the form is submitted. Obviously the code above is a fantasy  I just need the part to script uploading the images instead of clicking the upload button. My Autoit script will modify the innerHTML of this form to add the script for auto-upload. Is this doable?