The video stop at each frame

I’ve put photos on music and when the video run, it stops for 2 seconds at each frame. Why?

Have you exported your completed video first?
Shotcut won’t playback in real time an edited timeline that contains lots of decompressed images, transitions, filters and an audio track.

No, I didn’t. I just want to see how it goes while I do the video. So I understand that I have to export before.

Correct. But remember to save (ctrl+s) your work as you go.

Great. I tried it and it’s okay. Thanks.