Can I use a .jpg image and at the same time use a video generated for that image, as different files

Are you asking about licensing a video / images or contributing them. You are free to alter any assets that you license; therefore, I assume that grabbing an image from within a video is acceptable. You are also free to submit the images and videos as individual files.

Maybe you should write here in the fora in your language.

If I understand your request well, you have a video, and you want to submit that video to Adobe stock. In addition, you want to use one image of that video as a single image to be submitted to stock. I do not see a big problem with this, as long as you do not upload the whole video as separate images.