[TYPO3-dev] images are not working after upgrade from 4.7 to 6.2

[David Johnson]

After upgrade from 4.7 to 6.2 typo3 version, somehow I was getting some fatal error related to 'public_html', thanks to patch from - review.typo3.org/#/c/30526/ I am able to resolve the issue but right now, I am not getting any of the image uploaded to server after upgrade. I am getting following error.

#1401732564: Invalid file identifier given. It must be of type string and not empty. "NULL" given
47 TYPO3\CMS\Core\Resource\ResourceFactory::getFileObjectFromCombinedIdentifier(NULL)
46 TYPO3\CMS\Frontend\ContentObject\ContentObjectRenderer::imageLinkWrap("<img src="" width="" height="" alt="alternate text" />", NULL, array)

So we tried to debug the source code and found that cObject is not able to render FILES type - especially images. The typo3 backend seems to be working fine for me. Please shed some light on what could be cause in order to resolve the issue.