Find two images, one of which you want to fill a specific shape or mirror with the other
Go onto photoshop and import the two pictures
Take one image and select command a, and then command c
Click the other image and select command v
Unlock “layer one and background” on the right
Select the layer that has the image of the mirror
On the left select the lasso tool and begin to outline the mirror as precisely as possible
For the curvy section around the fingers the lasso is best. You can only do that small section with this tool and then click the remainder of the shape with the tool below the lasso.
Delete this section with the delete button on your computer
Now your image should be showing in the mirror.
Click the background layer to drag the image around into the correct positioning.
Export image