I did some a while back.
I’m no expert so all I did was,
First, make sure you have the layers panel open. (Click window, levels.)
In PS, create a new document. File, new, In the box enter- custom, 6”X4”, 300ppi, RGB, 16bit, white, s RGB, Square Pixels.
To set guidelines to aid positioning, click on View, and then on rulers.
Now right click on the rulers bar at the edge of the work area and select percent.
Now left click on the rulers bar and holding the mouse button down drag a guideline down to the 50% mark and release the button.
Now drag one in from the left to the 50% mark.
Set the crop tool, select crop, on the top bar click the button on the left hand side and in the dropdown box, click size and resolution. In the pop up box enter, width 3” and height 2” the resolution at 300ppi, OK.
Import the images and crop them to 3”X2”.
With the move tool selected, drag them into the card (The new document created.) layer.
Position them on the card, resizing with the “Transform, scale” command if a border around the images is desired. (More guides may be needed for the positioning and size)
If an oval image is wanted then select a picture that has been imported and sized, from your layer stack.
Now with the elliptical marquee tool selected draw the oval on the image, then go to edit-copy, edit-paste, this will put the selection in its own layer. Switch the original off by clicking on the eye to the left of its layer.
Check that the oval layer is on the top of the stack (If not click on it and drag it to the top.) this will put it above the other pictures allowing you to position it.
When your happy with the look flatten the image, by, clicking flatten image, in the dropdown box at the top right of the layers panel.
SAVE.
I think that’s what I did, If its wrong, hopefully someone will correct it for me.
Good luck with it.
Rhodese.
