"Key = x10hosting"
A key, for an encryption method? There are literaly 1000's+ of possibilities of ways to encrypt the contents of files. Hints like giving us the "key" doesn't help much.
"I just can't see the picture. In Mozilla FireFox it appears the following message, clearly stating that it is an JPEG image (?):
http://www.mohaa.x10hosting.com/fbi/PRIMARYT.JPG ; in IE6 it seems that the image doesn't exist."
That's the point of teh challenge. The image's "file" is encrypted, so if you try viewing the encrypted "version", you will get an error that the image is invalid and what not. The point is to decrypt it, and THEN view it to see what it is a picture of.