dropping photos into Avidemux video

[Faith]

I am trying to create a video to post online for a rescue group's adoptable dogs. I want to include stills to separate different parts of the video. I have the video, an MP4, and saved the first photo (a jpeg) as an MP4 as well. I opened the video, then tried to Append the jpeg/video, which is what the instructions say to do. I keep getting this error message: Attempt to open D: Avidemux videos/jpeg.mp4 failed! // Something failed when appending
I don't know what I'm doing wrong, and would love a step by step list of how to drop a jpeg in the middle of a video. Thanks to anyone who can help!
Faith

[Mr Chris]

I think what you've probably just discovered is that not all MP4s are equal and they don't necessarily play nicely with one another. Welcome to the world of video editing! It's a constant headache.

For what it's worth, the tool I think may provide the easiest route to achieve what you describe (ignoring the NLE options) would probably be TMPGEnc MPEG Smart Renderer. Drop the video in and trim; drop the photo in and set duration; drop the video in again and pick up where you left off; etc. etc. It's paid software, but it comes with an unrestricted 30-day free trial. Others may have better recommendations.

[Faith]

Thanks, Mr Chris! I discovered an online program that turns photos into 5 sec videos, but it sounds like your suggestion is an all-in-one solution!