[Flow] Image upload and displaying the uploaded image

[Cornel Widmer]

I've done a image upload for a news message in my flow application. As I can check, the file is uploaded and persisted as it should. The table typo3_flow_resource_resource has some entries and there exists a file in the folder "Data\Persistent\Resources" where the sha1 key matches and with the right file size.

Now I wanted to display this image on the webpage and use the "f:uri.resource"-Viewhelper. When the page loads, a new file is beeing generated in the folder "Web\_Resources\Persistent" with the sha1 key as filename and the right file extension (jpg). But the filesize is zero bytes.

In the source code of the page, the image is linked with the filename: "_Resources/Persistent/df7be9dc4f467187783aca68c7ce98e4df2172d0/Penguins.jpg". As I read in the documentation this path will be rewritten to the right filename.

At this point no image is displayed on the webpage. What is going wrong?

Are there some mod-rewrite settings to be done (.htaccess is active -> url-rewriting is working) 

Thanks for an hint (warmly desired) or solution (highly appreciated).