Welcome to the first Beta for ctools! This release fixes many little bugs that are viewable from the ctools dependent modules. Note, ctools_block and ctools_views are marked experimental and subject to change similar to other alpha modules.
#2864347: Colorbox Support Added configurable image style for dragging pins. This makes the imagepin possibly compatible with other formatters rather than just "image" and "responsive_image".
Please note that there's no update hook provided for updating from alpha2 to alpha3. When updating from alpha2 to alpha3, you'll need to manually reconfigure the imagepin settings in the Manage display section.