supported file types return - The file is not a known image format

ImageField uses the PHP function getimagesize to check if a file is an image. If this function fails, then you get the error you described, "The file is not a known image format." I'm not sure why this would fail on your server, since I'm not aware of any particular problems with IIS and imagegetsize().

An alternative (not a great one) would be to change your field type from "Image" to "File", which doesn't use this check.

Other than that, I'd ensure that you have GD2 installed (even though its not needed for getimagesize() it is needed to create the thumbnail). Try to switch to an Apache/Unix web server if at all possible, since that's the most common configuration and what nearly all developers use to test their modules.

Closing after 2 weeks with no response.

It could be a permissions problem. I just enabled write on the root folder from within IIS control panel and the problem went away. If I can figure out how to solve it on the files folder only without having to enable write on the whole directory and we will be sorted.

this is an issue of image module (see image.inc line 116 image_get_info($file) {..... } ) the issues caused by is_file($file) call. see http://ua2.php.net/manual/en/function.is-file.php for details

I want to bump and open this issue again as I am having this issue after upgrading to the latest 6.15 release on Microsoft-IIS/7.0.
It was working fine before on 6.14

The error reads: The selected file [filename].jpg could not be uploaded. The file is not a known image format.

NOTE: I am using the latest 3.dev release of CCK if that possibly has anything to do with it.

I will change status if I can track the root of the problem.

I just want to confirm that this is a problem with the latest 6.15 Drupal release on Microsoft-IIS/7.0.
If I roll back to 6.14 there's no problem.

There is no problem with both releases on a linux machine :)

+1 subscribe

Has anyone found a fix for this? I am having the same issue using Views Gallery.

I'm having the same issue as #7 fallsemo. I just upgraded drupal from 6.13 to 6.15 on Microsoft-IIS/7.0.

The fix posted in #307636: image_get_info() fails on IIS on new uploads worked for me with Drupal 6.15 on IIS 6.0. I just had to change the line in image.inc (but I had already done some tests to verify permissions were working).

thank you smsearcy! that fix worked for me...

Drupal 6.16
IIS 6
php 5.2.13

See #307636: image_get_info() fails on IIS on new uploads, this is a Drupal core issue. Thanks everyone for the sleuthing.

If it helps anyone;

I encountered this problem and traced it to the Temporary Directory (as set in admin/settings/file-system) being full.

I guess this error can occur for a multitude of reasons on the server config. I was originally suspecting permissions.

For me, the issue was caused by having two load balanced servers and the load server doing load-balancing in round robin method. The multiple image upload will then result in uploading to two servers and then some of the images can't be found for processing. We have to configure the load balancer to use session affinity based on cookie.

Me facing the same issue in drupal 7 site.

Error message displayed while uploading an image : The file could not be saved. An unknown error has occurred.

Any solution for this?

My php version is 7.2