Images do not display in secure filesystem.

I believe you need to add an implementation of hook_file_download because you aren't accessing the uploaded file but rather the scaled file. When you go to the url system/files/filename.WIDTHxHEIGHT.ext the upload.module can't find that file in its table so it doesn't return any headers. I think you can fix this problem in one of two ways.

1. Insert the scaled image file in to the upload.module table (this is probably the proper way to do things)
2. Use the following code to map between the new filename and the uploaded filename:

/**
 * Implementation of hook_file_download()
 */
function slideshow_file_download($file) {
	// Map the slideshow scaled image back to the original uploaded image
	$size = variable_get('slideshow_size', '640x480');
	$extension = pathinfo($filename, PATHINFO_EXTENSION);
	$original_uploaded_file = preg_replace("/$size\.$extension/", "$extension", $file);
	return module_invoke('upload', 'file_download', $original_uploaded_file);
}

I had to do this in the 4.7.x version of this module but I am having other problems with the slideshow.module at this point so I can't be sure.

I would rather document my fix here and see if it helps other people while I track down my other problem.

I just realized that the proper code in the 5.x version of this module is:

function slideshow_file_download($file) {
	// Map the slideshow scaled image back to the original uploaded image
	$path = variable_get('slideshow_image_path', 'slideshow');
	$original_uploaded_file = preg_replace("/$path\//", "", $file);
	return module_invoke('upload', 'file_download', $original_uploaded_file);
}

I do not know the state of the slideshow module, but can this be closed or should a patch be generated? People are still having this issue as of May 2008, would a patch be accepted?