Edit: Issue is with Remote stream wrapper module, not Imagecache External module. The token GET param "?itok=xxxxxxxx" is being url-encoded, resulting in path like "...../image_19.preview.jpg%3Fitok%3Db8LE0Kbe"
The url-encoding happens in DrupalPublicStreamWrapper::getExternalUrl().
The trace is something like theme_image_style() -> theme_image() -> file_create_url() -> DrupalPublicStreamWrapper::getExternalUrl()
Module stack:
Package Name Type Version
Administra Module filter (module_filter) Module 7.x-2.x-dev
tion
Chaos tool Chaos tools (ctools) Module 7.x-1.2+31-dev
suite
Chaos tool Page manager (page_manager) Module 7.x-1.2+31-dev
suite
Core Block (block) Module 7.20
Core Color (color) Module 7.20
Core Comment (comment) Module 7.20
Core Contextual links (contextual) Module 7.20
Core Dashboard (dashboard) Module 7.20
Core Database logging (dblog) Module 7.20
Core Field (field) Module 7.20
Core Field SQL storage (field_sql_storage) Module 7.20
Core Field UI (field_ui) Module 7.20
Core File (file) Module 7.20
Core Filter (filter) Module 7.20
Core Help (help) Module 7.20
Core Image (image) Module 7.20
Core List (list) Module 7.20
Core Menu (menu) Module 7.20
Core Node (node) Module 7.20
Core Number (number) Module 7.20
Core Options (options) Module 7.20
Core Path (path) Module 7.20
Core RDF (rdf) Module 7.20
Core Search (search) Module 7.20
Core Shortcut (shortcut) Module 7.20
Core System (system) Module 7.20
Core Taxonomy (taxonomy) Module 7.20
Core Text (text) Module 7.20
Core Toolbar (toolbar) Module 7.20
Core Update manager (update) Module 7.20
Core User (user) Module 7.20
Developmen Devel (devel) Module 7.x-1.3
t
Fields Bundle copy (bundle_copy) Module 7.x-2.x-dev
Media File entity (file_entity) Module 7.x-2.0-unstable7+3
9-dev
Media Media (media) Module 7.x-2.0-unstable7+2
5-dev
Media Media Browser Plus for Media 2.x Module 7.x-2.0-dev1+1-dev
(media_browser_plus)
Media Media Internet Sources Module 7.x-2.0-unstable7+2
(media_internet) 5-dev
Other Colorbox (colorbox) Module 7.x-2.3+5-dev
Other Imagecache External Module 7.x-2.0-beta1+0-dev
(imagecache_external)
Other Libraries (libraries) Module 7.x-2.0+5-dev
Other Multiple forms (multiform) Module 7.x-1.0
Other Remote stream wrapper Module 7.x-1.0-beta4+0-dev
(remote_stream_wrapper)
Views Views (views) Module 7.x-3.5+38-dev
Views Views UI (views_ui) Module 7.x-3.5+38-dev
Core Bartik (bartik) Theme 7.20
Core Seven (seven) Theme 7.20