Unable to load .jpg or .jpeg image after browsing file system

I've tracked it down to image_gd_resize() in image.gd.inc. [I don't have imagemagik installed]

Here's what's happening in my case:

image.module:_image_build_derivatives() decides it needs to build a thumbnail image
and eventually calls image_scale().

image_scale() calls image_gd_resize() which calls image_gd_open($file, $extension)

image_gd_open() fails for jpg's because (on my installation) imageCreateFromjpeg() does not exist,
whereas imageCreateFrompng and gif do.

so image_gd_open() returns FALSE, causing image_gd_resize() to return FALSE, which sets
$status to FALSE on line 806 of image.module which causes _image_build_derivatives()
to return FALSE, which zaps out $form_state['values']['images'].

I tried changing lines 814 thru 820 of image.module to:

if (!$status) {
drupal_set_message(t('Unable to create scaled %label image', array('%label' => $size['label'])), 'error');
// return FALSE;
unset($images[$key]);
} else {
$images[$key] = $destination;
}

but drupal insists on having a thumbnail, so it complains and puts nasty messages on the screen.

BTW, there is a potential size related issue in image_scale() because it can return false if it detects 'scaling up'. I think the right answer is to create the thumbnail by copying the original.

I don't think that is a problem if we invoke image_scale_and crop() to create the thumbnail, because it doesn't have the 'don't scale up' logic.

do you still want me to try this for different size files?

I traced my problem down to a configuration error/feature [user error?] in building PHP 5.2.5 on my mac. So, as far as I'm concerned this is resolved.

I've also attached a short patch to 'images.module' to keep '_image_build_derivatives()' from blowing away the entire $form_state['images'] array. I think it's a good thing to do because it keeps the upload working even if the thumbnail can't be built.