I made an action for you...
customthingy.zip
Go to the actions tab and LOAD it
all you have to do before running it (from the batch automation menu) is create a new document that is big enough in both dimensions for every image that you have in the folder to fit in. Or just make it 8000x8000@300dpi to be safe and save you the trouble of checking. you can always crop off the excess area afterwards.
*make sure you TICK the overide action OPEN and SAVE AS boxes.
also tick the override color profile box.
then Proceed.
It will then open all images in the chosen folder.. select ALL and cut and paste into the document you previously created.
easy peasy lemon squeezy !