This website contains links to software which is either no longer maintained or will be supported only until the end of 2019 (CKFinder 2). For the latest documentation about current CKSource projects, including software like CKEditor 4/CKEditor 5, CKFinder 3, Cloud Services, Letters, Accessibility Checker, please visit the new documentation website.
If you look for an information about very old versions of CKEditor, FCKeditor and CKFinder check also the CKEditor forum, which was closed in 2015. If not, please head to StackOverflow for support.
Sometimes a user can try to upload a file which isn't an image file but appears as if it would be a one. Example: You have a text file called document.jpeg and you try to upload it. If you enable the function by setting it to true:
$config['SecureImageUploads'] = true;
the program will check the dimensions of the file. If they are zero the file isn't an image and it will be rejected be the CKFinder.