Select 6 Vertical Photos, Rename 1.jpg to 6.jpg

Select 4 Horizontal Photos, Rename 7.jpg to 10.jpg

Email each 10 Photos sets separately.

You may need to zip the Photos into a file

Select Template Accordingly > OPEN WITH ADOBE ACROBAT

Open Adobe Acrobat Pro

Edit>Edit Text & Images>

Add Images>Right Hand Click>Arrange>Send to Back

File>Export to>Image>JPEG