I am also facing the same problem, Could you please help and let me know what exactly needs to be done.
When i generate the responsive HTML, the images are missing in the output. Then i reinserted the image. then generated the HTML5 again. the output file starts showing the image.
After this i closed the robohelp file and reopened it again. Then i generated the responsive HTML5 output. Then same problem arises again. I have to reinsert the images again to fix the issue
The Robohelp file that i am working on is very big. the problem appears in multiple pages.
I have branched this post to a new thread as the thread originally used is four years old and a lot has changed in that time. I also edited o/p to make it clearer and removed the word "file" as that makes it sound like a CHM output.
You haven't said which version of RoboHelp you are using. If 2019 is it Classic or the New UI?
Please define big.
This looks like the same question as in the thread at https://community.adobe.com/t5/robohelp/project-file-has-the-image-but-responsive-html5-not-displayi...
That is already being dealt with so I don't understand raising the issue again elsewhere. I will now lock this thread so that others don't try to help here and split the answers.