[Typo3] image in FE doesnt appear

[Horn Gabor]

Hi,

i have a strange problem w/ a site. Image uploading in BE works 
perfectly (eg image w/ text component), i can see the thumbnail in the 
images part, etc. They also appeared correctly in the FE which already 
has some pictures in the content. After a few months we started to work 
on the content again,  adding more content elements, and now on the FE 
all the new images we upload appears as

<img src="" width="" height=""  border="0" align="top" alt="" title="" />

in the source and obviously no image can be seen :) Even if i attach new 
images to exisiting "image w/ text" content elements, where the "old" 
picture can be see, the new appears in the html as the above. It's in 
the same record, and on the BE both attached images can be seen.

Do you have any idea please what should i check?

thx, hirisov