When you have a new PowerPoint document open, to insert a picture / gif you have to click on the "insert" tab and then on "image".
A new window will open in which you have to find the picture you are interested in,
select it and then click "insert".
The picture will appear on the card
PowerPoint.
It will be marked with "stamps" which, after "grabbing" with the mouse, allow for possible reduction or enlargement of the image.
However, if you hover the mouse over the center of the photo, holding the left mouse button you can freely move the photo and change its position on the card.
You have to remember, however, that the objects you insert will be "movable" only in the preview of the slide show or after saving the project.