I search the forum for 1 day now and have not found a solution to this yet.
I have a fresh ss 2.4.3 install. I can see the image with ftp in the asset/Uploads folder but if i go to the url it wont show I only get an 500 intrenal server error. if I go to the tab files & images and clik on the image I can only get name and not the image thumbnail.
I can upload images, if i go to the image pane in where I insert the image to the content I only get the image name not a thumbnail.

I even did a fresh install of SS 2.4.3 but it did not do any good.

Any clue to this?

I had to change the .htaccess in folder asset
Changed the line "php_flag engine off" with "RewriteEngine Off". the it worked.