This lightweight free video editing software can turn your images to videos automatically under the Automatic Video mode, which will save your time if you don’t want to do any editing. You can also use the Custom Video mode to trim, resize the video, change audio volume, add filters, text, motion and 3D effects. However, it hasn’t a timeline e and some advanced features such as split tool, green screen, video stabilization effects are missing.

KineMaster is one of the most powerful video editor apps available. You can do the basics like most of these other video editors can. However, this one includes multiple video, image and effect layers. Additionally, there are audio filters, chroma key (for your green screen fans out there), various video effects, transitions, and more. It's not as powerful as a full desktop editor. However, this gets much closer than most other competitors. We would recommend this for actual video production (at least for stuff like YouTube). You can use it for free in trial mode for a while. However, you'll need the $4.99 per month subscription to get everything forever.
If you’ve got a fitness app, you might have segmented your potential audience into 2 groups. Men who want to get huge lifting weights, and men who want to get ready for a marathon. As you can imagine, they have completely different goals, and their interests and behaviour will reflect that. You need to take this into consideration when you create your images.