Aperture Photometry Tool, v. 2.6.4, is now available:
There is an enhancement in this release.
Added option to Preferences menu to choose between two different sizes of crosshair mouse cursor, regular (default) or large:
Preferences > Set Image-Display Attributes > Crosshair-Cursor Type
The crosshair cursor is seen when hovering over the main image-viewing panel. The large size is a customized version, and may not work under Mac OS X El Capitan.