https://spdf.gsfc.nasa.gov/pub/data/ibex/hi/maps/images/release_1/ibex_hi_maps_images_release1_readme.txt

This directory provides PNG-formatted display versions 
of the first (Release 1) 6-month, all-sky maps of 
spacecraft-frame ENA (hydrogen) fluxes from IBEX-Hi 
energy bands 2-6. 

Data of this directory are superseded by the Epoch 1
data of the Release_2 subdirectories. 

Files within this Release_1 directory are named as 
HiMap-oBBB-oCCC_720x30-flux-D.EEE, where

BBB is the orbit number of the first orbit contributing to the file
CCC is the orbit number of the last orbit contributing to the file
(BBB and CCC include leading zeroes.)
D gives the energy band number (2, 3, ...6)
EEE is "txt" for the digital files, "png" for the images.

Energy bands 2-6 have FWHM ranges of 0.52-0.95, 0.84-1.55,
1.36-2.50, 1.99-3.75, 3.13-6.00 keV, respectively.