New Iphone X took most of photos as .mov or Heic

I want my photos as .jpeg as they are easier to manipulate.

Under iOS 11, the iPhone X can record/store videos as H.264 or HEVC (H.265) MOV and photos as JPG or HEIC files. If you want the files recorded/stored as H.264 MOV video and JPG photos, then set the iPhone X Camera app Format preference to the "Most Compatible" option. On the other hand, if you want the files recorded/stored as HEVC MOV and HEIC files but transfer the data to other devices as H.264 MOV and JPG files, then set the iPhone X Photos app Transfer to Mac or PC preference to "Automatic" to perform "on-the-fly" transfers as H.264 MOV and JPG files.

How to convert .mov to .jpeg, most of the .mov are only 1-2 seconds?

If you wish to extract a single frame from an MOV file already transferred to a Mac and the MOV file is QTX playback compatible, try the following...

1. Open the MOV file in the QTX player.
2. Scale player window if/as desired.
3. Scrub the playhead to the frame you want.
4. Press "Command-C" to copy the target frame to the clipboard.
5. Open the Preview app and select the "New from Clipboard" File menu option.
6. When the Preview app preview window opens, select the "Save..." or "Export..." File menu option.
7. Select the format in which you want the photo saved (i.e., in your case a JPG file) and press the "Save" button.

Many other media apps have similar options to capture/convert MOV frames to JPG files but workflows may vary slightly. Use the app/workflow your prefer most.