'pesterchum.ico' contains pc_chummy.png upscaled with Gimp to 16x16, 32x32, 64x64, 128x128, and 256x256. The previous icon only contained 16x16 and 32x32.
'pesterchum.icns' is pc_chummy.png upscaled to 512x512 with Gimp, converted to .icns with Pillow.
Should hopefully solve the awful anti-aliasing and interpolation artifacts some systems introduce when upscaling the icons.
