I choose the screencasting tool Doodlecast Pro which I have as an iPad app. It allows the use of backgrounds that are already available as well as the importing of your own photos and pdfs. It is vey easy to use. The feature that I love is that it is easy to pause, change your background and continue on with the video recording seamlessly.
I gather all of my pictures first, decide what I want to say for each one, and then load the first one and start recording. It is easy to annotate with free form lines or straight lines. You can change the color and weight of the lines, add an arrow controlled by the touch screen and erase as needed. The only thing I don’t like is my recorded voice, but that is a problem with anything that I record and then listen to.
I always save the videos to my gallery and then move it from there to where I need it. I usually save as a medium quality video to save space. The videos are then very easy to upload to whatever format I would like. Here is a short video I made on google earth engine. I am unable to open the program currently so I used screenshots to make this video so the views and quality are not as good as they should be.
This is a great tool for the online classroom because it allows you to quickly make a custom video for your class. This would be a great way to give basic information. The screen capture lets you cover exactly the material you want to share with your students. It is also a great way to give information and directions to those students who learn better from watching a demonstration instead of from reading directions.
I think that adding this skill to your teaching repertoire would help the online teacher as wel as the teacher who sees their class in person.