The application currently has an option upon launching, to place a desktop file in ~/.local/share/applications so Hiri shows up in the applications list. Currently, that desktop file is configured to point directly to a PNG file in the install path of Hiri. Gnome's icon packs are stored in /usr/share/icons. If the install of the desktop file, also moved the hiri image to /usr/share/icons/hicolor, and changed the icon value to just hiri. Then other icon packs like papirus could easily include an icon that matches there theme which would automatically work.