I can confirm that the problem is when "~" is in the URL.
I’ve tested 3 separate installations on 3 different machines. All MODx 2.0.2-pl traditional setup.
(BTW, none of those installations have ImageMagick installed.)
Local WAMP installation works fine. There was no "~" in the URL.
Localhost info:
Windows NT ARES 6.1 build 7600 ((null)) i586
gd
GD Support enabled
GD Version bundled (2.0.34 compatible)
FreeType Support enabled
FreeType Linkage with freetype
FreeType Version 2.3.9
GIF Read Support enabled
GIF Create Support enabled
JPEG Support enabled
libJPEG Version 6b
PNG Support enabled
libPNG Version 1.2.37
WBMP Support enabled
XBM Support enabled
Does not work (broken thumbnails, errors in error.log) at the development URL that contains "~".
Shared hosting:
PHP Version 5.2.14
Linux 2.6.18 i686
gd
GD Support enabled
GD Version bundled (2.0.34 compatible)
FreeType Support enabled
FreeType Linkage with freetype
FreeType Version 2.2.1
GIF Read Support enabled
GIF Create Support enabled
JPG Support enabled
PNG Support enabled
WBMP Support enabled
XPM Support enabled
XBM Support enabled
On my Ubuntu server it works fine without "~". When I setup the user_dir module for apache and tried again with the URL http://ip/~testuser/ the thumbnails broke like on the shared hosting.
My Ubuntu server:
PHP Version 5.2.6-3ubuntu4.6
Linux webserver 2.6.28-11-server
gd
GD Support enabled
GD Version 2.0 or higher
FreeType Support enabled
FreeType Linkage with freetype
FreeType Version 2.3.9
T1Lib Support enabled
GIF Read Support enabled
GIF Create Support enabled
JPG Support enabled
PNG Support enabled
WBMP Support enabled
So I think it’s fair to say that phpthumb has problems with "~" in the URL.
This might not be such a huge issue, and might even be phpthumb’s dev’s problem. But I feel it’s at least a problem for me because my clients can’t see their uploaded image while the site is in development. It takes away from the otherwise great, polished MODx experience.