Suppose that we need to handle icons and then sent the file to them in PSD format, or save them in the same format with some slight changes.
Not to make every effort in the processing of each file, open them in Adobe Photoshop. The main condition for subsequent operations is the same size of the original files!
So, you press the keyboard shortcut: Ctrl + A (Select all), then Ctrl + C (Copy). Thus, we select the entire image area, then copy it to the clipboard.
Now create a new file based on the clipboard, i.e. we need from the item creation menu of the document you select Clipboard.
Insert the image into the newly created document by pressing Ctrl + V.
Then go to the rest of the photos that you want to move to a separate file, and repeat the above procedure, i.e. copy the entire area of the picture and paste it into a new file. Thus, you should have several layers.
Now save the file, you change what you need.
This image processing technique can be used to edit products on the website, change background for all photos and for other purposes.
The main advantage of this treatment is the subsequent editing, because you can always open just 1 file with multiple images.