This is a small selection of graphic editors and utilities for some of the platforms allowed on the competition.

Atari

Atari Interlaced Studio 1.4.7 (Windows): Graphic editor with support for many graphic modes, including interlaced ones. Can export as executable files (.XEX). Link

Apple

Ghetto Image Converter (PC): PPM to HGR2 image converter, requires a PC with lua 5.1. Link

Commodore

NUFLI editor (C-64): NUFLI editor. Link

Project One (Windows): Editor/Converter for Hires/Multicolor/AFLI/FLI/IFLI/Drazlace modes. Link

GangEd (Windows): Very basic Hires/Multicolor & semigraphic modes editor.  Can export Hires/Multicolor as executables. Link

ConGo (Windows): Image viewer/converter, can export Hires/Multicolor/IFLI/FLI/MCI as executables. Link

MSX

MSX Paint IV (MSX2): Screen 5, 6, 7 y 8 editor. Requires mouse. Link

piroPaint 9918 (Windows): Screen 2 editor. Link

MSX Screen Conversor (Web): PNG/GIF/JPEG to Screen 2, 5, 6, 7, 8 y 12 converter. Link

Sinclair

OCP Art Studio (Spectrum 48K): Complete graphic editor. Link

ZXpaintyONE (Web): ZX-81 semigraphics editor, written in HTML5. Link

ZX-Paintbrush (Windows): SCREEN$ editor for the ZX-Spectrum. Link