@Rayandbar Most video editors have an option to take a screen grab. I use Davinci Resolve (a free version but very memory intensive).
Look in the file or edit menu for “Export” whilst the frame still you want is on display. It will give you an option to where you want to save it to.
Open the file in Photoshop or any software that allows you to upscale or resize and edit away.
The quality is generally good if using a 4k video as the donor.
If you dont have a video editor (DJI have the free editors Lightcut app or the Fly App) then you can use the Print Screen) function on your PC. Not usually as good but acceptable for many media uses.