Images doesn't show up after uploading

Hello, and thank you for reading this post.

Somehow my Drupal installation (hosted) won't show any images I post/upload with either Image Picker OR "create content/image"
No matter how I upload it, it simply won't show up, not in posts, not in the gallery, not in the FCKeditor - basically - not anywhere.

BUT...

It does upload! And it even creates the thumbnails for it.
Switching to "Source" under the FCKeditor - reveals that it links correctly to the images.

What I have been trying:
- Setting quickupload to true (as indicated in many forums & blogs I've googled for hours and hours), still doesn't work.
- Installing dozens of modules, various ways to upload images - they all UPLOAD perfectly well, but it still won't show up in the editor.
- Updating etc.

What works:
- Uploading of images
- Displaying embedded images when linking from external sources
- Displaying images from my hosts server...when manually editing URL's and typing in the entire path. Funnily - not the path to where Image Picker keeps the images though...those does NOT show up.
- Status report show no errors.

What doesn't work:
- Displaying images in posts...uploaded with Image picker or FCKeditor's own upload feature
- Images posted with the "create content/image" function
- Displaying the images separately in a browser - directly from the URL path to eg. /sites/all/default
- Images in the gallery, pressing their "links" shows no images

Can anyone offer an advice to where I proceed from here?

Many thanks in advance,
/Tommy