[TYPO3-install] Images only displayed if aligned "center, below text" and in original size (TYPO3 4.1.1 @ Hetzner SH500 account)

[René Weimar]

Hello,

I'm having the following Problem with a TYPO3 4.1.1 installation (tried 
4.0 as well with the same result)

Images are only displayed correctly if I do not resize them and align 
them centered below the text.

Otherwise there is a black area where there should be the image or there 
is no image at all. If so, there is not even a re3ference to the image 
in the html source code. All thumbnails are rendered correctly though!

Changes in the Install-Tool didn't help so far.

I've never experienced a problem like this before - at the same time 
it's my first try to install TYPO3 in a shared hosting environment 
(SH500 account from www.hetzner.de - TYPO3 is supposed to work there). 
I'd write them an E-Mail but I don't know what to tell them so far.

My first question would be if images that are aligned right or left in 
the text are somehow resized automatically as they're not displayed in 
this case even if I don't resize them explicitly.

Any ideas?

Thanks
René