[jdarwood007]

Fixes #8650

Not really needed as 3.0 is cleanly exiting. But I figure the extra check is worth it.

[albertlast]

This check stops every thumbnail from being made.

$dst_name is already $this->source . '_thumb.tmp' when resize() writes to it, so file_exists($dst_name . '.tmp') looks for …_thumb.tmp.tmp, which never exists. The method then returns false before the rename, and the real …_thumb.tmp is left on disk.

I made a 400×300 PNG and called (new SMF\Graphics\Image($source))->createThumbnail(100, 100):

	result	files left
release-3.0	SMF\Graphics\Image 100x75	image, image_thumb
this PR	false	image, image_thumb.tmp

The check would have to be file_exists($dst_name) before the substr(), or file_exists($dst_name . '.tmp') after it.