How to create a educational video by only using your voice and some photos
Use PowerPoint.
The truth is that the latest version of it can do nice transitions so the presentation is not dull at all.
At the end, you can export as a video to Mp4. If used properly you do not need video edition at all.
Do not use less than HD for your videos. The resolution may not be important to you, but the viewers are used to Full HD.