The same issue is raised earlier with post 12927. though it still not get resolved with viewer v3.4
so raising again with groupdocs.
Rending image type file in the html based rendering is not working correctly.
Sometimes images are displaying too small when its render first time, while rendering from cache its displaying large. In both the scenario its not displaying based on its actual size. Even image type files are not rendering in chrome and edge browsers. I have attached few images files you can verify it.
We have also observed files containing images (i.e. Docs, PPT) having issue in HTML based rendering.
Please look into theses issues and let me know in case you need any further information.
PFA for issuing document.