NEW USER - Missing tool? - Fill in corners of rotated image

Hi Community,

I am new to Photo Express, I use to use Photo Elements 5 but that has recently stopped working (to old a piece of software i guess). So i am trying Express to allow me to slightly amend holiday snaps.

Essentially, on the sample image above, i have taken my image and rotated it to straighten the image. I would then have used a tool to copy and fill in the now blank corners. (when i had access to Photo Elements 5). I cannot recall the name of the function but it looked like a rubber stamp on the tool bar.

Is there a similar tool or a tool within Adobe Express that could achieve this function?

Thank you for help.

(I am using a PC, not a smart phone)