C64 Graphics Explorer

This app is about the Commodore 64. Or, more precisely, it is built around the C64. The first version came out in February 2026. Version 2.0 and 2.1 followed in August with a substantial rewrite under the hood. It is becoming a fun little app that I enjoy using.

The Problem

I wanted an app where I could drop in a Commodore 64 PNG file and view it with CRT simulation.

I don’t know about you, but I like looking at C64 demos and images. I usually watch demos in an emulator, where the CRT emulation is pretty good, but downloaded images are only visible in these tiny previews. You have to zoom in, every image has slightly different colors, you can’t see the character cells, and so on.

I felt there was a need for an app that could display a C64 image more like it might have appeared on a monitor from the era. It needed CRT simulation, an appropriate aspect ratio and colors, plus a way to inspect the pixels.

So I made one.

Download

You can get the app from the macOS App Store — it’s free!

How It Works

You can drop in any 16-color image and it will display it with Colodore colors and CRT emulation. You can explore, zoom, switch between CRT emulation and raw pixels, examine classic C64 interlaced images and see how they are constructed, or export the result as an animated GIF. It is all quite flexible.

I also thought of people who are not quite as C64-obsessed as I am, so I included a few sample images from among my favorites. You can immediately get lost in the details of one classic image or another.

Motivation

There is one image I spent quite a lot of time analyzing.

Using the VICE monitor/debugger, I extracted the overlay and underlay sprites from the display routine, reconstructed the full rendering in Aseprite, split it into layers, and included those layers in the app so they can be toggled on and off.

One of the comments on Mermaid’s image says:

I love this. The outstanding storytelling and style is one thing. But I feel the need to tell the world how extremely well this is executed from a technical perspective. Flawless, Mermaid. Flawless.

— Archmage

That perfectly describes how I feel too. The world really should know that this is not just a simple witch picture. It is a witch picture built with 42 multiplexed sprites layered above and below the main artwork, adding color, highlights, and other details. With C64 Graphics Explorer, you can switch the layers on and off one by one and see how Mermaid put the whole thing together.

As a bonus, I also got one of her early sketches, which I reconstructed in Aseprite so you can see exactly how each character changed.