Step 2: Create a copy of your image for editing
Open a new default picture using the [new] function.
Paste your copied picture onto the new blank background using the [paste] function.
Right-click the newly pasted image and select [Fit Background to Selection].
Close out the original photo so you don't accidentally change it. It should not ask you to save any changes. If it does, you may be closing the wrong file. (Measure twice, cut once).
You should now be left with a copy of your original photo ready for editing.