Ah, perhaps it is something else.
Currently you have a maximum height setting of 280 px for most image types. As many tests may exceed that, this may contribute, and have given a false positive in non-wiki forums with the mod disabled. Therefore, it's very likely that you are getting the issue where:
Uploading an image with dimensions higher than the max allowed as a wiki image would upload it as a thumbnail.
However, you have a max of 0 for jpg files, so technically this should all be skipped when uploading a file with the jpg extension. However, there is still a max file size setting for jpg files, so if the file size is exceeded, the image will be resized and trigger the bug mentioned above. Uploading a jpg within the set max file size will be uploaded correctly.
I was mistaken above when I said that the jpg conversion must be a server configuration problem. Further investigation reveals that vBulletin will convert the image to a jpg when resizing is needed (this will be particularly annoying in the image forum where the title has to match, and some users might not have permission to modify the title at this point).
To fix the main problem, in
vault/extensions/image/image_class_thumb.php, perform the following replacement in 2 places. Find:
Code:
$vault_dimensions = explode(',', $this->registry->options['vaulti_thumb_width']);
$maxwidth = intval($vault_dimensions[0]);
$maxheight = intval($vault_dimensions[1]);
Replace with:
Code:
if (
$this->registry->options['attachthumbssize'] == $maxwidth AND
$this->registry->options['attachthumbssize'] == $maxheight
)
{
// this is a thumbnail not a resize
$vault_dimensions = explode(',', $this->registry->options['vaulti_thumb_width']);
$maxwidth = intval($vault_dimensions[0]);
$maxheight = intval($vault_dimensions[1]);
}