Creating Motion Graphic Templates

Hi,

I want to design a few simple photo slide templates for a YouTube video.

The idea is to include placeholders for the images so that in Premiere Pro, I can easily import the desired pictures into the template and reuse the same template wherever and whenever necessary. Similar to lower thirds title templates that are commonly available, where, in the appropriate panel, you can customize the font size, style, color, etc. I am primarily concerned with the images, but adding descriptive text and being able to adjust aspects of the animation also interest me.

Would someone be so kind as to point me in the right direction? I'm willing to take an online course, but unsure what specific course description or level of instruction I should be looking for. Perhaps building a template of this type might be better in Premiere Pro and not After Effect.

Thanks for any assistance you can provide.

Kind regards,

Mark Carr